Having a few problems with my new car

[atomicradish]

I posted awhile back about getting a new car. It's a '94 Mitsubishi Galant GS. To get it in running order, we had to get 2 new timing belts put on it, along with having 5 valves replaced and a complete valve job. It drove really well for say 150 miles after we had this work done on it, but now another problem has arose. The car did sit for 6 years, so we did expect to run into a few problems...

When you accelerate hard, around 4,000 - 5,000 RPMs, the car holds back. Even if you mash the accelerator to the floor, it wont go any faster. The car lurches as though it is receiving gas intermittently, and it wont go above said RPM. It does not matter what gear the car is in, it always does this. At first I thought it might just be bad gas since what was in it was 6 years old. However after putting a lot of octane boost, and $10 worth of premium in it, it still continues, just as bad as before.

I doubt it is relevant, but this started to happen a little bit after changing the oil in it to a synthetic blend (valvoline 10W-40 max life).

If anyone can help... try to remember that I'm mechanically illiterate.

thanks

[QDM]

First thing that comes to mind is the fuel filter.

Q

[omgwtfbyobbq]

Then the fuel pump, in that order.

[unstable bob]

Gasoline that has been sitting turns into a varnish like state w/i a year's time.
The path the gas must travel to your fuel injectors begins with a strainer/ filtration device on your fuel pump. This can get clogged up, limiting the fuel flow any further. Bad thing about this scenerio is that the fuel tank must be removed to access the fuel pump to fix this problem. The next culprit as mentioned is a clogged fuel filter. This is a much simpler fix. I just don't happen to that kind of luck. I'm in the process of resurrecting a car that has been sitting for about 2 years, and I'm doing new tank/new pump/and new filter. Plus I had to get rid of 15 gallons of "old" premium fuel...:(
Good luck with your endeavor.

[atomicradish]

Thanks for the advice guys.

Does anyone have an idea why it didn't start this until recently? Like I said earlier... it drove good for about 100 miles before this problem started to crop up.

[unstable bob]

Thanks for the advice guys.

Does anyone have an idea why it didn't start this until recently? Like I said earlier... it drove good for about 100 miles before this problem started to crop up.

Gradual buildup of the gas sediment ["varnish"] on the strainer or in the fuel filter, causing a strangulation effect on fuel flow.

[atomicradish]

Gradual buildup of the gas sediment ["varnish"] on the strainer or in the fuel filter, causing a strangulation effect on fuel flow.

Thanks. :thumbup:

[omgwtfbyobbq]

Plus I had to get rid of 15 gallons of "old" premium fuel...:( Worst smell ever. :thumbdown:

[unstable bob]

Thanks. :thumbup:

No prob.

[unstable bob]

Worst smell ever. :thumbdown:

I actually work with a guy who smells worse...:rolleyes:

[landspeed]

Another possibility would be the cat getting blocked in the exhaust - which happened to me with my old (Rover) Metro!. It was like a rev limiter / speed limiter - but, if you changed up a gear e.g. 3rd to 4th, you could go a bit faster - presumably as the engine gave more power for the same amount of exhaust gases!.

When you rev the car, does it give a good flow from the exhaust (s?).

If it is the fuel filter / something like that, then it won't necessarily give problems at the same RPM all the time. If you rev it in neutral when it is stopped, can you go higher than 4000-5000rpm?.

[atomicradish]

Would running fuel injector cleaner through a couple of tanks of gas clear it up without removing the fuel tank?

[brucepick]

I don't know if unstable bob has worked on Mitsu Galant's. I've changed a couple in-tank fuel pumps and their filter screens on our cars (not Mitsu though) and it did not require tank removal. Still a PITA, you access the tank's innards via an o-ring'd hole at top of tank, via the trunk or hatch.

The main fuel filter is a separate item, would be somewhere in the fuel line but I'd expect it to be outside the tank, probably under the car. In the good old days they were in the engine compartment but that was for low pressure systems with carburetors.

[brucepick]

Would running fuel injector cleaner through a couple of tanks of gas clear it up without removing the fuel tank?

Definitely worth a shot. Supposedly Techron is best, or at least one of the best. Then there's Seafoam, which cleans everything in the fuel path including the valves. I'd use Techron first; Seafoam kicks up a lot of carbon and junk and blows it out the exhaust.

[atomicradish]

I went ahead and got Seafoam. I didn't see techron anywhere, and I figured that it needed the most powerful stuff out there, considering how bad it is.

Put some in, let it idle for 5 minutes or so, then I drove it and pushed it hard. It was still doing it though. The car would lurch a little bit, but it would eventually go on to a higher RPM, though it definetly fought to do so. I brought it home, let it idle for another 10 - 15 minutes, then drove it again... and it was worse than ever. I couldn't even get it over 3,000 RPMs this time. The oil light also flickered on and off when it idled. I could only assume that the cleaner was causing this.

I can only hope it will be better with a little more driving. It was definetly kicking out a lot of carbon which is good. I head out to college soon and I'd like to have the car running nice before then. If there is anything I can do without having to involve my dad (nightmare) then I'm all for it.

Does anyone know where I could possibly get a schematic of where the fuel filter and pump are without having to buy a repair manual?

[Ryland]

I would also simply do a tune up on the car, replace those parts that are recomended every few years, you might also have a compression test done to make sure that the head work that was done fixed all the valves, as valve float could do simaler things, as the valves wouldn't close all the way, and that could come up because of compressed valve springs.

but really, do a tune up first.

[unstable bob]

I don't know if unstable bob has worked on Mitsu Galant's. I've changed a couple in-tank fuel pumps and their filter screens on our cars (not Mitsu though) and it did not require tank removal. Still a PITA, you access the tank's innards via an o-ring'd hole at top of tank, via the trunk or hatch.

The main fuel filter is a separate item, would be somewhere in the fuel line but I'd expect it to be outside the tank, probably under the car. In the good old days they were in the engine compartment but that was for low pressure systems with carburetors.

Never did a fuel pump on a Galant. And it seems like every thing I've ever worked on required dropping the tank. Although I will admit to breaking out the wiz wheel and creating an access panel on a few late model Camaros and Firebirds, since those cars also require dropping the rear end to get the fuel tank out. ;)

[unstable bob]

Does anyone know where I could possibly get a schematic of where the fuel filter and pump are without having to buy a repair manual?

Well, I would say it is a given that the fuel pump is located in the fuel tank, and hopefully it is self explanatory as to where the tank is, and what it looks like. The pump fits into the tank through an opening in the top of the tank, and you have to figure out if the pump is accessible through the trunk or hatch as Bruce suggested, or if the tank has to come down. As far as the fuel filter goes, just head down to the local parts house and pick up a new filter, then follow the fuel line out of the tank until you find the item that matches up w/ the filter you just bought. Not sure how Mitsu secures their filters in the line, though. Sometimes there are threaded fittings, sometimes there are pressed in connectors, sometimes a combo of both, or might be sumthin' I've never even heard of! :eek:

[ffvben]

if your car has a MAF it could give the same lag when you acell if its bad. it feels like its running out of fuel the higher your rpm is and some cars stall out just as you press the gas.

[atomicradish]

I picked up a fuel filter today. Hopefully can get it installed tomorrow. Someone else I talked to said it could be the throttle body (idk what that is). Hopefully this will clear it up.

[atomicradish]

Alright. Good news so far.

I believe I found the fuel filter. I got under the car the best I could and did not see it underneath. I opened up the hood, searched around for a little while and spotted a highly similar looking piece, only weathered. It was attached against the frame of the car on the side nearest the driver. Leading directly from this piece was a line, which fed four different items (shaped like a spark plug). I presume that those are the fuel injectors.

Could I possibly be right?

If so, this is a major step for me. I was almost tempted to try to replace it myself.

[bobski]

Someone else I talked to said it could be the throttle body (idk what that is).
The throttle is a round metal plate that blocks off airflow coming into the engine. Stepping on the gas pedal twists that plate (via a cable) until, with the pedal to the floor, the plate is edge-on to the air flow, presenting almost no restriction. In gasoline engines, it's the throttle plate that controls power output. In older cars, the throttle is part of the carburator; In fuel injected cars, it's generally a separate component.
The throttle body is simply the part that houses the throttle plate. It's generally a round air passage bolted to the beginning of the intake manifold (yeah, yeah... "what's an intake mainfold?"). It's generally a few inches long, made of aluminum, has a cable attached to it and is connected to the air filter box by a large tube. If your car uses a MAF (Mass Air Flow) sensor, it will be located between the air filter and throttle body, so don't confuse the two.
Depending on engine design, the throttle body may incorperate other components such as a throttle position sensor, MAP (Manifold Absolute Pressure) sensor, idle control valves and even the fuel injectors.

I guess pics would help. Lucky you, I've got the engine out of my car ATM. :)
http://i6.photobucket.com/albums/y208/bobski3333/Z6IMlabeled1.jpg
http://i6.photobucket.com/albums/y208/bobski3333/Z6throttleAngle1.jpg
http://i6.photobucket.com/albums/y208/bobski3333/Z6throttleClosed1.jpg
http://i6.photobucket.com/albums/y208/bobski3333/Z6throttleOpen1.jpg

[bfg9000d]

I had something very similar happen to me. This is what solved it for me. Your new oil change should consist of the smaller bottle of marvel mystery oil and 4 bottles of whatever your choice of oil. Then from their I recommend getting some B12 chemtool. With only about 1/4 of a tank left add B12 Chem tool through until you just about run well into the red. This will blow any gunk from the injectors. before doing even that I recommend replacing fuel filter and fuel pump (new fuel pump is always helpful) When you finally get the gas tank drop clean the gas tank out with some gasoline this will ensure their are no loose particles sitting at the bottom. Also replace the ignition module if you got one and put some newer spark plugs in . Check the fuel lines to see if their free of foreign material. Also ensure that the belts are in good shape and take the alternator down to a auto store like autozone and have them do a alternator check this is always good regardless if you are having problems or not. Put new distributor on and wires but if you have a distributor less car then minus that. Make sure you coolant temperature sensor is in good share. This is always a very overlook part on the car. Allot of times the manufactures will make them of plastic and they do fail and the ones you get at the auto store are made of a good metal and normally they last forever. It sounds like going overboard but its always better to go ahead and knock out all the likely problems then trying to take down and rebuild again.

[bobski]

Also replace the ignition module if you got one and put some newer spark plugs in . [...] Put new distributor on and wires but if you have a distributor less car then minus that.
I was thinking it could be an ignition problem as well, but given the info, it could just as well be a fuel supply issue or clogged cat.

[atomicradish]

Well the car has an ignition problem as well. Either a bad wire, or a bad relay switch somewhere, so right now there is a push button wire to the solenoid and battery somehow.

Thanks for the pics and explanation bobski. I had ready something like that on howstuffworks.com but it wasn't as in depth.

[bfg9000d]

another thing I recommend doing is get a code reader for that car. Being 94 its probably the older style code reader. I still recommend getting one and try to fix anything that comes up on the code reader. This will help allot it might not fix the problem your faced now with but it will let you know of any other hidden problems you might face down the road. Plus getting all the codes cleared off the car is a great feeling both to you and how the car will act. Allot of older cars will act just fine but when put up to a code reader can give a whole host of codes that might result in problems with the car.

[n0rt0npr0]

bfg,
I'm pretty sure a code reader for a 1994 mitsubishi is gonna cost upwards of $500. It's not the same as the ford/GM/Chrysler 1994's two prong device....in fact a paper clip works on 1993's, 1994's and 1995's are OBD1.5's,....they are the expensive ones to pull codes from.

Atomicradish,
I would vote that its your fuel filter causing the problem. The fuels we are using now have a minimum of ethanol in them, and ethanol is an incredible cleaner, so all that old gas varnished in the tank and lines and the new gas cleaned it out and deposited it in the filter.

[bfg9000d]

yes it still needs to be done especially if its never been check. Go to any good mechanic shop they will run the codes for you. Autozone will do it for yeah as well. Pending what it is.

On a side note Its always funny when you take your car to a toyota dealer service center and you hand them the code error and they write them down and give them to the mechanic. I did this a couple of times and each time the mechanic personally came out and talk with me about the car. Not their stupid middle man that just says your car needs this and that and you gotta pay this and that. They know I'm not F**** around. Man I cant stand those middle man people that come up to talk to you about your car. They dont know nothing beyong what the mechanic told them. Of course I'm out of the warranty part of my car now so If something goes wrong I fix it myself.

[n0rt0npr0]

Autozone will not scan codes on ANY car older than 1996.
Also, since the vehicle is a 1994, IF the SES light is not on, there will be no stored codes in the computer. It wasn't until 1996 that codes could be set and not activate a light.

yes it still needs to be done especially if its never been check. Go to any good mechanic shop they will run the codes for you. Autozone will do it for yeah as well. Pending what it is.

On a side note Its always funny when you take your car to a toyota dealer service center and you hand them the code error and they write them down and give them to the mechanic. I did this a couple of times and each time the mechanic personally came out and talk with me about the car. Not their stupid middle man that just says your car needs this and that and you gotta pay this and that. They know I'm not F**** around. Man I cant stand those middle man people that come up to talk to you about your car. They dont know nothing beyong what the mechanic told them. Of course I'm out of the warranty part of my car now so If something goes wrong I fix it myself.

[bfg9000d]

Are autozone will run codes on older cars. They ran it for me on my 92 Taurus. It verys from autozone to autozone. Although most don't

[atomicradish]

It was not the fuel filter.

Replaced it, and it is still driving bad, although it does idle much smoother now. The filter that was in it was full of water and rust.

Someone we know who is a mechanic says it is either the throttle position sensor or the MAP sensor. Does this sound possible? Nobody has suggested it here so far. Going to change out the sensors on this car with the other Mitsubishi we have for parts.

We do not have an AutoZone here. Only Advance Auto. Would they check the codes on it?

[unstable bob]

It was not the fuel filter.

Replaced it, and it is still driving bad, although it does idle much smoother now. The filter that was in it was full of water and rust.


That crap in the filter had to be pumped out of the tank...don't forget about the tank, fuel pump and strainer still being culprits...

[ffvben]

map/maf are sometimes combined in the same sensor as in some nissans.

[bobski]

map/maf are sometimes combined in the same sensor as in some nissans.
Is that possible? The MAP measures manifold vacuum... I would think that pressure changes would screw with the MAF's accuracy. I could see an atmospheric pressure sensor maybe, but MAP?
Why would you even need both a MAF and MAP sensor? Yeah, some newer engines with drive-by-wire throttle will go WOT while cruising to reduce pumping losses... Under those conditions, a MAP sensor would be pretty much useless for measuring air flow. But otherwise, there are pretty much two methods for metering air flow - speed/density using a MAP sensor, and direct mass air flow measurement.

[skewbe]

...Why would you even need both a MAF and MAP sensor?...

Exactly

[atomicradish]

MAP and throttle position sensors were both replaced along with a loose wire (found where it went) to no avail.

The tank will probably have to go down unless anyone else has another suggestion. I can already hear my dad *****ing about it :(

[bobski]

The tank will probably have to go down unless anyone else has another suggestion.
Has an ignition system problem been ruled out?

[mrmad]

It is possible your timing belt skipped a tooth on the cam gears? If so, the engine would be running like crap

[n0rt0npr0]

I second this question. Maybe the plugs are fouled out? I still think a simple test a mechanic with the tool to do it could yay or nay whether the converter is clogged?
You could pick one of these backpressure testers up yourself: http://www.tooloutfitters.net/exhaust-back-pressure-tester-p31676.html


Has an ignition system problem been ruled out?

[brucepick]

Seafoam again - did you run it thru the engine via a vacuum hose line like I remember it says on the bottle?

For a real good Seafoam procedure, see this:
http://www.turbobricks.com/forums/showthread.php?t=35053

The C.W.T. process is basically:
[EDIT: First warm up the engine]
Hook up a thin vacuum line to manifold (between throttle body and the head somewhere).
Learn what 3K rpms sounds like so you can run it at 3K using the throttle wheel on the intake.

Suck up a quart of (preferably distilled) water thru the vacuum line. Suck a few seconds, pull the hose out of water, suck a few more seconds, etc. Work the throttle wheel to keep engine from stalling when needed, try mainting 3K rpm. This actually does a lot of cleaning - turns to steam in the cylinder.

Now do the same with the bottle of Seafoam.

When done go out and drive it hard. Up to redline multiple times.

You might see big clouds of gray junk out the tailpipe during any step of the procedure.

[Bill in Houston]

Is anyone besides me afraid that the Seafoam and water might really break something? Like a rod or valve or something?

[Red]

Is anyone besides me afraid that the Seafoam and water might really break something? Like a rod or valve or something?

The trick is to either suck it up slowly or pour it in slowly. If you dump the whole can of Seafoam or a whole bottle of water in, you could hydrolock the motor.

[brucepick]

Is anyone besides me afraid that the Seafoam and water might really break something? Like a rod or valve or something?

You're sucking in far more air than water. Sucking in straight water is definitely bad karma. I'm pretty sure the Seafoam itself is combustible so that shouldn't be an issue.

[atomicradish]

I just put a proportionate amount of Seafoam as compared to gas in the tank. That was one of several different uses it had according to the bottle.

I do not believe the plugs are fouled. New plugs were installed when the valve job was done.

Senior Member




Join Date: Mar 2007
Location: Temecula, CA
Posts: 159


Rex-O-Saurus
5.39L/100KM
43.64 MPG(US) It is possible your timing belt skipped a tooth on the cam gears? If so, the engine would be running like crap

I don't think so. The engine runs great at idle (except when it ran low on fuel once) and when driven at a steady speed. In 5th gear I do not notice this problem at all. Only when accelerating or occasionally when traveling in a lower gear does it come up.

If it is the fuel filter / something like that, then it won't necessarily give problems at the same RPM all the time. If you rev it in neutral when it is stopped, can you go higher than 4000-5000rpm?.

Sorry I just now noticed this part of your post quite a while back. In neutral you can go over 4,000 - 5,000 RPM. I have not noticed this problem so much in neutral. It is not always the same RPM, but usually it is in the 4,000 - 5,000 range. Occasionally when it is really giving me problems I notice it at even 3,000. This is a major problem because this car runs at 2,900 RPM or so at 60 mph in 5th gear. Again I haven't noticed it in 5th gear, but this can be a headache when I only need 4th gear and it rountinely runs at 3k or so.



There are quite a few suggestions here. If I were a bit more mechanically inclined I would try them all out on my own, but since I am not, is there a way that I can try to eliminate them just through simple driving tests? Perhaps I am not being detailed enough in my descriptions? For clairty sake I will go ahead and list all of the ideas (that havent been disproven) below...

1. Strainer/Filtration device on the fuel pump
2. Blocked catalytic converter
3. Valve float
4. Ignition problem of some sort
5. Timing belt skipped a tooth

facts about this car:

1. DOHC with 2 brand new timing belts just recently put on
2. New sparkplugs
3. Had gas sit in it for 4+ - horrible odor when burned (all the bad gas has been used up by now though)
4. When accelerating, normally around 4,000 - 5,000 RPMs the car jerks as though it is not getting enough gas. Will not accelerate further until a higher gear is selected.
5. On extremely bad days it will do it around 3,000 RPMs (typical running rpm for this car)
6. The problem seems to be lessened by adding gas to the tank
7. The problem appears to be augmented when the car is running low on fuel.
8. Once when I ran the tank really really low (to presumably use up all the potential bad fuel) the engine idled extremely low (under 500 rpm) and kept dying on me. I had to gun it up to 4k rpm in neutral and quickly shift to 1st to get it out of the driveway. I coasted through stop signs to avoid stalling out. However after I had driven about 10 miles and warmed the engine up, it idled fine at each stop light I was forced to stop at. Since new gas has been put in, this problem has not come up again.
9. A relay switch somewhere in the ignition system (or perhaps a bad wire) has forced us to reroute the electric signal by connecting a wire to the battery and the solenoid and so the car now has a push buttom system to turn it on. It cranks perfectly fine with this arrangement
10. Brand new starter put on it

Items already tested:

1.) adding seafoam to the tank (further cleaning attempts with seafoam may be in the works)
2.) New fuel filter installed
3.) MAP sensor replaced
4.) Throttle position sensor replaced
5.) Loose wire which somehow connects to the engine block was replaced and reattached

I hope I have collected ideas together well enough. There are so many suggestions... I hope I also filled in the gaps as well. With this information, I am also hoping someone can tell me what potential problem source should be looked into first (whichever appears most likely).

[n0rt0npr0]

Did they also replace your plug wires?

[mrmad]

After reading your description again, if it really seems to be affected by the amount of gas in the tank, then it is likely fuel pressure related. Before the PIA of changing the fuel pump in the gas tank, I'd consider getting a fuel pressure gauge. It would tell you if your pump is working properly. If the pressure is low, you'd be running lean, and the symptoms of this would probably show up on acceleration first, that's when the ECU is trying to make the mixture richer.

Sorry, I don't know what the fuel pressure your car is supposed to be, but you should be able to find that info on the internet somewhere.

[n0rt0npr0]

mrmad,

Thats a great idea. If he doesn't want to do it himself, just call about 8 repair shops close to home and try to get the best price. Ask: can you put a fuel pressure gauge on my car and tell me where the pressure sits during acceleration? And then, if its good pressure or not? Shouldn't be more than $20, and they might even have some awesome suggestions.

[ffvben]

Is that possible? The MAP measures manifold vacuum... I would think that pressure changes would screw with the MAF's accuracy. I could see an atmospheric pressure sensor maybe, but MAP?
Why would you even need both a MAF and MAP sensor? Yeah, some newer engines with drive-by-wire throttle will go WOT while cruising to reduce pumping losses... Under those conditions, a MAP sensor would be pretty much useless for measuring air flow. But otherwise, there are pretty much two methods for metering air flow - speed/density using a MAP sensor, and direct mass air flow measurement.

brain fart, no map/mafs combos. i was thinking of baro reading from the maf sensor.

[atomicradish]

After reading your description again, if it really seems to be affected by the amount of gas in the tank, then it is likely fuel pressure related. Before the PIA of changing the fuel pump in the gas tank, I'd consider getting a fuel pressure gauge. It would tell you if your pump is working properly. If the pressure is low, you'd be running lean, and the symptoms of this would probably show up on acceleration first, that's when the ECU is trying to make the mixture richer.

Sorry, I don't know what the fuel pressure your car is supposed to be, but you should be able to find that info on the internet somewhere.


Thanks! I will definetly try this out.

[atomicradish]

Thanks for the help guys. It looks like it's the fuel pump after all.

Took the car in yesterday to the same guy who replaced the head and the valves. He's a friend of my dad's and he drove the car for a little while and immediately identified the problem as the fuel pump (before driving it he said the plug wires might need changed).

Of course, my dad basically ignored that and said we should run a few more tanks of gas through it to see if the problem would magically disappear. Well, it didn't. I drove it out today to get a pizza and it was so bad I had to pull over 3 times, and the last time it just completely died on me. The rigged up "push button" start we had for the car also went. It shorted out on me and the wires connecting the battery and solenoid caught on fire.

Completely ****ing stressful day. Unfortunately to get anyone to help me with my car I have to get stranded on the damn road. I will be taking auto mechanics at the first available opportunity so I don't have to deal with **** like this ever again.

[ffvben]

always use a fuse. this way no fires start ;)

[atomicradish]

Replaced the fuel pump today with another fuel pump from the parts car we have. The pump was easily accessible through the back seat, so it only took a couple of hours to do.

The pump that was on it was rusted, and the strainer was chogged full of rust, dirt, and other stuff. Really, it's amazing that the car ever ran at all with it like it was. I'll take pics and post them tomorrow.

[mrmad]

Replaced the fuel pump today with another fuel pump from the parts car we have. The pump was easily accessible through the back seat, so it only took a couple of hours to do.

The pump that was on it was rusted, and the strainer was chogged full of rust, dirt, and other stuff. Really, it's amazing that the car ever ran at all with it like it was. I'll take pics and post them tomorrow.

Glad you got it fixed. Hopefully your gas tank isn't so full of dirt and rust that it will clog the new fuel pump up.