Ask GTP About Your Car Problems/General Questions

[Philly]

That all makes sense now. Thanks for the advice!

Well done on the M too 👍

 

[Jim Prower]

Yeah, you've got an issue there. Cat's probably clogged.

Basically, you have enough resistance to flow that the exhaust gases are looking for an easier way out...

Thanks for the advice. I now have a good excuse to replace it, (or gut it,) now.

Tailpipe broke off at the cat. so now it's gonna be REALLY loud until we can order and get a new cat, and pipe...or flange to mount the tailpipe on.

 

[Heldenzeit]

I have a question that I will be amazed if anyone can solve as Mitsubishi, a unichip specialist, myself and a mechanic could not solve.

This was on a 3.5L 2002 Mitsubishi Magna. The issue arose on its own and got worse as time passed. Car had a unichip, cams, exhaust, CAI and an aftermarket fuel pump.

The problem: Car would turn off while crusing on a freeway (100km/h) and would not turn back on unless you turned the key to completely off, waited about 10 seconds where a relay would click, then the car would start again. The car would also at times turn off while accelerating from lights (but turn back on).

Unichip was removed and the car would run fine, so unichip was replaced and the problem came back after a few hours of driving. ECU was tested and showed to be fine. A third unichip was fitted and tested, same problem arose. The second unichip was fitted onto a car afterwards and had no issues what so ever.

This problem arose fairly suddenly in a 1 month period, no changes were made to the car in the mean time, the car had been running a unichip for at least 2 years beforehand with the same tune.

The car is gone now but would be interested to know if anyone has heard of a similar thing before or even know of what the solution was?

That sounds to me like a fuel delivery problem, but I couldnt say without looking at it or replicating the problem.

 

[J-PaP]

That sounds to me like a fuel delivery problem, but I couldnt say without looking at it or replicating the problem.

To add to my previous post, I had a fuel pressure regulator fitted to monitor fuel pressure, Even when the car turned off, fuel pressure was still there so the car was not cutting fuel meaning it had to have been cutting spark to turn off.

The unichip even at one point had the map removed completely so the car just had the unichip in place, but the car was running on standard settings. Issue still appeared.

 

[Heldenzeit]

In order for an engine to run, it has to have spark, fuel, and air.

Driveability 101.

 

[nd 4 holden spd]

I have a question that I will be amazed if anyone can solve as Mitsubishi, a unichip specialist, myself and a mechanic could not solve.

This was on a 3.5L 2002 Mitsubishi Magna. The issue arose on its own and got worse as time passed. Car had a unichip, cams, exhaust, CAI and an aftermarket fuel pump.

The problem: Car would turn off while crusing on a freeway (100km/h) and would not turn back on unless you turned the key to completely off, waited about 10 seconds where a relay would click, then the car would start again. The car would also at times turn off while accelerating from lights (but turn back on).

Unichip was removed and the car would run fine, so unichip was replaced and the problem came back after a few hours of driving. ECU was tested and showed to be fine. A third unichip was fitted and tested, same problem arose. The second unichip was fitted onto a car afterwards and had no issues what so ever.

This problem arose fairly suddenly in a 1 month period, no changes were made to the car in the mean time, the car had been running a unichip for at least 2 years beforehand with the same tune.

The car is gone now but would be interested to know if anyone has heard of a similar thing before or even know of what the solution was?

What's a unichip?
Commodores can get problems like that when the crank angle sensor gets damaged/doesn't work properly. With a normal computer the car would kick into life again taking less than a second, but with an aftermarket computer chip the computer shuts the engine down to protect from any possible damage- thinking like a race computer.

In order for an engine to run, it has to have spark, fuel, and air.

Driveability 101.

👍

 

[Duke]

It was the red stuff. Is there a process involved? I'm sure I can find some white at home, when I get back. Hopefully that'll help.

That explains it. The red compound is one notch finer than 1000-grit sandpaper. It's made to be the first step in bringing a lacquer job up to shiny. Rub the car with red (which you've already done). Wash it, and rub it again with white polishing compound. This is finer than the red stuff, and will bring back more shine. Wash it, and buff it with Meguiars Mirror Glaze or something similar for the real shine.

[edit] Treed massively by ///M-Spec.

Hesitation....

Lately my car's been hard to start, particularly in wet weather, when the engine stumbles on takeoff and at low rpms. Now, considering the age and fuel delivery system of the car, I'm thinking I might have a couple issues...

1. Vacuum leak: aside from all the vacuum lines, what needs to be looked at or replaced? should I check the PCV?
2. Ignition coil: How do I check this, and make sure It's getting enough spark?
3. Cat. converter air tube: Instead of pulling air back into the cat, it's pushing exhaust into the air cleaner housing. Is it time for a new cat or something?

The "catalytic convertor air tube" doesn't pull air into the cat, it pushes exhaust back into the intake stream the be reburned. That's called Exhaust Gas Recirculation (EGR) and it's probably functioning just fine. I doubt the cat is plugged, though that does happen. Most likely symptom of a plugged cat is general loss of overall power, rather than intermittent periods of crap and fine running.

My guess is that the oxygen sensor(s) are due for replacement.

 

[Jim Prower]

The "catalytic convertor air tube" doesn't pull air into the cat, it pushes exhaust back into the intake stream the be reburned. That's called Exhaust Gas Recirculation (EGR) and it's probably functioning just fine. I doubt the cat is plugged, though that does happen. Most likely symptom of a plugged cat is general loss of overall power, rather than intermittent periods of crap and fine running.

My guess is that the oxygen sensor(s) are due for replacement.

Duke...

It doesn't have an oxygen sensor. It's got a 2bbl Carburetor. Remember, It's a 1988 Nova: the Fuel-Injected versions were only offered in this year, only with the 4A-GE, and are rare as hen's teeth. Thus, mine is the 4A-LC, SOHC, 8V, Carbureted version.

That being said, it does have an EGR valve, but I believe it sits on the exhaust manifold, not the Catalytic Converter, and exhausts into the intake manifold. It's not a crossflow engine, either, so they can do that easily, because the intake and exhaust manifolds are on the same side.

 

[J-PaP]

What's a unichip?
Commodores can get problems like that when the crank angle sensor gets damaged/doesn't work properly. With a normal computer the car would kick into life again taking less than a second, but with an aftermarket computer chip the computer shuts the engine down to protect from any possible damage- thinking like a race computer.

Sorry I'm going to keep adding info as this goes on as I simply forget everything that was tried out as it was about a 3 month long "investigation".

Unichip is a piggyback computer. I'm not 100% familiar with its capabilities but from what I understood I don't think it had any of those capabilities.

Crank angle sensor, AFM, fuel pump, distributor, throttle position sensor and idle speed controler were all swapped over (borrowed off others with the same car) at one point.

The only electronic device that had to do with the engine that was not swapped was the ecu which was tested.

In order for an engine to run, it has to have spark, fuel, and air.

Driveability 101.

I don't understand? Well obviously car needs the 3 but when I am cruising at 100km/h or accelerating air is there as I have the throttle open (it's a mechanical throttle body so it could not close itself), Car showed normal fuel pressure when it would stall and not start again (during freeway driving was only time this could be measured as while taking off it normally would just start again) so only spark is left right?

 

[///M-Spec]

That all makes sense now. Thanks for the advice!

Well done on the M too 👍

NP! Let us know how it goes and take some pics when you're done!


M

 

[homeforsummer]

Okay peeps here's one:

Recently my Fiesta has started holding onto revs when I change gear. It literally only happens when the clutch is disengaged as I change gear, the revs either stay as they were when I pressed down the clutch or they even rise a little, and in experimenting keeping the clutch disengaged they naturally die again after a second or two.

I've tried revving the engine in neutral but the revs don't "stick" then like they do if I'm passing between gears.

Driver error can be ruled out - I don't keep my foot resting on the throttle enough for it to rev up during a gearchange, and it's not happened in the last 5.5 years of driving so I assume it's the car.

Anyone care to hazard a guess? The throttle isn't sticking in gear at all, only when changing up. Gunk somewhere on the linkage between throttle cable and throttle body maybe?

 

[Heldenzeit]

I don't understand? Well obviously car needs the 3 but when I am cruising at 100km/h or accelerating air is there as I have the throttle open (it's a mechanical throttle body so it could not close itself), Car showed normal fuel pressure when it would stall and not start again (during freeway driving was only time this could be measured as while taking off it normally would just start again) so only spark is left right?

I would'nt directly be able to condemn it as a spark problem, but my statement is just basic engine diagnosis theory.

If the manual fuel pressure guage says it has pressure, then you must have fuel. But it might not nessecarily be getting to the injectors. But if it only dies at a certain time, it must be a singe stroke that is having problems.

Even if the throttle plate is open, you might not be getting air via a clogged filter.

Even when my V8 Camaro was running on 6 cyl for a while due to grounding out plug wires, the car would still run, but very badly.

This one is difficult.

 

[Famine]

Okay peeps here's one:

Recently my Fiesta has started holding onto revs when I change gear. It literally only happens when the clutch is disengaged as I change gear, the revs either stay as they were when I pressed down the clutch or they even rise a little, and in experimenting keeping the clutch disengaged they naturally die again after a second or two.

I've tried revving the engine in neutral but the revs don't "stick" then like they do if I'm passing between gears.

Driver error can be ruled out - I don't keep my foot resting on the throttle enough for it to rev up during a gearchange, and it's not happened in the last 5.5 years of driving so I assume it's the car.

Anyone care to hazard a guess? The throttle isn't sticking in gear at all, only when changing up. Gunk somewhere on the linkage between throttle cable and throttle body maybe?

Yep. My Mk3 1.3 Fiesta developed a similar issue. The throttle cable was catching on something in the engine bay (though I forget what it was) so it didn't retract properly, leaving the throttle open.

 

[homeforsummer]

Ah ha, cheers. I'll take a look at it tomorrow in the light and see where it's catching. It only does it intermittantly.

 

[McLaren]

This is a car-related question, and I don't think it warrants a thread.

Some background first. Lately, I've been driving the TL a lot. I think I've put 200 miles on her easy within the past month. It's been so inviting, and so much fun to drive. And a lot of people have been giving it compliments lately, calling it badass, cool, nice, etc., asking about performance and such.

Thus, I think I want to keep her. I've still got a lot of time left with her though to make the decision, but it's already grabbing at me. I've been having an itch to mod her a lot as well. New exhausts, rims, etc, minus the bodykit. However, if I do this now, I'd def. be forcing myself to keep the car after the lease. Another issue comes with this as well. When the lease ends, plenty of new cars will be out. The Camaro, Challenger, 1 Series, etc. I'm extremely interested in the Camaro so I already have a choice of whether to keep the TL or go for a Camaro. Decisions, decisions.

But, I now have a few questions, so your opinions are valued.

1: Is the TL worth keeping or should I shoot for the new Camaro or something else?

2: What performance mods/tuners are available to the TL-S?

 

[nd 4 holden spd]

Well you can have a sports coupe, or the family car (what a TL is isn't it?). I guess it depends on what you need more. Of course I'll go the Camaro hands down.

 

[Thirdeye]

In terms of the TL, I would say it's hit or miss. They're excellent cars except the Automatic Transmission is VERY trouble prone. Acura/Honda extended their warranty on them I believe, because they were all failing prematurely. If it's a manual transmission, go for it! Great looking car, and excellent mated with the manual gearbox. Also, what year is the TL you're looking at? The late 90's early 2000's had lots of problems with the gearbox. After 2004 was when they fixed the problem.

 

[McLaren]

In terms of the TL, I would say it's hit or miss. They're excellent cars except the Automatic Transmission is VERY trouble prone. Acura/Honda extended their warranty on them I believe, because they were all failing prematurely. If it's a manual transmission, go for it! Great looking car, and excellent mated with the manual gearbox. Also, what year is the TL you're looking at? The late 90's early 2000's had lots of problems with the gearbox. After 2004 was when they fixed the problem.

I have an '07 Type-S model on a lease. Right now, I'm considering whether or not I want to give the car back and get a Camaro, or something else. My 5's lease is up at the same time but I highly doubt anything but another Bavarian will be replacing it.

 

[Tornado]

That's actually a toughie. I really like the Camaro, but something about the TL just clicked with me the first time I saw one. I would hold onto the TL for one reason:
You won't be able to buy any model Camaro for anywhere near list. And with the new TL coming out, I'm sure whatever dealer you will return yours to will be very anxious to get rid of it to clear lot space.

 

[///M-Spec]

I have an '07 Type-S model on a lease. Right now, I'm considering whether or not I want to give the car back and get a Camaro, or something else. My 5's lease is up at the same time but I highly doubt anything but another Bavarian will be replacing it.

Give the TL back. Give the 528 back.

For same money in lease payments, lease E90 M3 Sedan. Collect 200 wyns.


M

 

[Duke]

Give the TL back. Give the 528 back.

For same money in lease payments, lease E90 M3 Sedan. Collect 200 wyns.

Since you like to track your cars (or would at least like to), quit tracking leased iron. Give both cars back, lease something else pleasant to drive, and BUY a dedicated track car that you could afford to wreck.

 

[///M-Spec]

^ I thought you were talking to me for a sec, but you must be talking to Reventón and just referencing my post.

I thought he bought that Civic Si for a track car??

But I agree. Don't drive anything to the track that you're not ready to throw away. Autocross if you want to have fun in a leased car. I was looking at an E36 318 sedan last week to start a track car build. About 4k buys a nice E36 these days. No damn reason to take a 20k+ car to the track.


M

 

[McLaren]

Give the TL back. Give the 528 back.

For same money in lease payments, lease E90 M3 Sedan. Collect 200 wyns.


M

That would be something. I'll consider it that, then, actually. 2 years should hopefully give 'em time to drop in price.

^ I thought you were talking to me for a sec, but you must be talking to Reventón and just referencing my post.

I thought he bought that Civic Si for a track car??

But I agree. Don't drive anything to the track that you're not ready to throw away. Autocross if you want to have fun in a leased car. I was looking at an E36 318 sedan last week to start a track car build. About 4k buys a nice E36 these days. No damn reason to take a 20k+ car to the track.


M

I did get the Si for a track car. I just haven't had the time to drive out to the track since it's all the way in Cresson, Texas. That hasn't stopped me from a couple autocross deals, though.

 

[Danny]

My car's temperature gauge is always hovering between hot and cold, at almost exactly the same places, swaying lightly every now and again. This is even from a cold start, and long stints at motorway speeds. Should I worry, even though it recently passed it's MOT?

 

[///M-Spec]

Does your gauge show oil or coolant temp?

If it is the typical coolant temp gauge, then the behavior you describe is normal. These gauges are designed to stay dead in the middle under all but the most extreme conditions. This is because they want to avoid people calling up their dealers in a panic if the needle moves half a degree one way or the other.

It should, however, show "cold" immediately after start up. Most cars take several miles of running before coolant is anywhere near operating temp.


M

 

[Danny]

Does your gauge show oil or coolant temp?

At the risk of revealing what little I know about cars, I'm not sure. I think it's coolant however. If it's a fault then I could ask my dad to check it out when he's back.

Thanks for the help.👍

 

[nd 4 holden spd]

G'day g'day, for the first time my Mum has a question for someone who might know. She owns one of the old Subaru wagons with a carby boxer 4, and most importantly the ability to change between Front Wheel Drive and 4-wheel-drive hi or low. My question is, what's the last model of any Subaru wagon that had the ability to change drive wheels like that? I think she is after EFI and air con, power steering might be nice too I guess, so what's the latest model that did the drive wheel swaps?

 

[exigeracer]

Here's a general question for you, more of a trivia:

What do the brands BMW, Toyota and Saab share in common?

 

[buickgnx88]

Not American?

 

[Prosthetic]

Here's a general question for you, more of a trivia:

What do the brands BMW, Toyota and Saab share in common?

They all make cars?