View Full Version : Stalling at low revs - help a chick with a GT28RS out!

01-13-2008, 09:33 PM
Hey guys (and possibly gals :)

I bought a '98 1.8T last year from a guy who did the GT28RS upgrade with 440c injectors, and a FMIC. He had Mika tuning, but I wasn't that happy with it so had Chris Tapp give me two boost programs using the stock tuning. It seemed to be running OK for a couple of months, but then it started stalling when I was in a parking lot or something. For example, it would go up to about 2000 revs, and then when I put the clutch in it would go right down to zero and stall. I also got a CEL of multiple engine misfire recently, and a mechanic changed the MAF (he said it was running lean too). It got rid of the CEL, but the stalling continues.
I just moved to Victoria, BC and wasn't happy with the first mechanic, so brought it somewhere else and they think it is still the MAF. Is it possible that the MAF is faulty? (it is Bosch).
Does anyone have any ideas on what else it could be. The car also doesn't seem to like running below 2000 when I am driving along too...it is as if there is a slight hesitation just before I accelerate up past it.

I know I am not as technically minded as most of you on this forum, but I really don't know where else to ask advice. [;)]

01-13-2008, 09:44 PM
possibly coil packs gone bad?

01-13-2008, 09:48 PM
Yeah, from reading some of the other posts, I thought of plugs or coilpacks. Is there a way they could test that without buying new ones? Thanks for the suggestion :)

01-13-2008, 09:48 PM
On the chris tapp tune you should be using a ford 90mm maf unless chris rescaled his maps for a smaller mad. Perhaps check your ICM.

01-13-2008, 09:51 PM
Actually, Chris didn't do his regular tune for this setup since I didn't have a clutch that could handle it nor a hi-flo cat. He did mention the MAF upgrade too, so he told me he just gave me 15 and 20 psi programs using stock tuning in the meantime. Sorry what is an ICM?

01-13-2008, 10:02 PM
its the ignition control module. its a silver oval piece with two connectors on it near the intake/tubro side. It should be off the MAF harness. Do you know what cylinders are misfiring? usually misfires on cylinder 2 are a dead giveaway its the ICM.

so when you step on the clutch it stalls or on the release?

01-13-2008, 10:17 PM
Ah, ok, cool thanks! It was multiple cylinder misfire, so not sure if cyl 2 was part of that.

It is when I step on the clutch, so the revs come down fast, and it just doesn't recover.

01-13-2008, 10:23 PM
thats very stange. So if you are stopped in neutral and step on the clutch it stalls? Hmmmmm

01-13-2008, 10:29 PM
No, it is when I am trying to park the car, for example, so I bring it up to 1800-2200 revs while backing up, then put the clutch in, and the revs drop down, but they don't stop at idle - it goes to zero.

01-13-2008, 10:33 PM
Ok so like in between shifts. Gotcha. Does the car idle well? Has the car recently had its battery unhooked?

01-13-2008, 10:40 PM
Right. And as I said, it doesn't stall when I am driving along normally on the road, and downshifting through the gears from higher revs. It idles pretty well - there is a slight resonating effect to it in that the revs move very slightly up and down while idling, but it is very very slight. Sometimes it may jump up above 1500-1700 when it has almost stalled....it is like it is overcompensating, but again, only under the low rev conditions.

01-13-2008, 10:44 PM
Ehhh...i kinda wanna say its because i rarely hear of someone with a tapp tune haiving a good idle. My idle is at 1200 -1300 rpm. I may have a vac leak though.

Does your vac read 22-23 in/hg?

I guess go over basics like looking for vacuum leaks, intake leaks.

01-13-2008, 10:49 PM
Ok, will do - thanks again! Actually, I remember when I got it inspected a year ago they said that some of the vacuum hoses were slightly cracked and could cause a boost leak, so perhaps that is a good start.

01-13-2008, 10:53 PM
Yup good luck!

01-13-2008, 10:59 PM
vacuum leak!

my 325i did the same thing, the intake manifold gasket had cracked and it would die every so often upon clutch disengagement.

it wont be your gasket, it will be your vac lines.

Don Supreme
01-15-2008, 11:08 AM
Its either
1) vac leak
2) bad maf
3) blown coil(s)
4) bad icm

03-03-2008, 01:13 PM
My mechanic thinks it is the throttle body...it is an expensive experiment if it isn't the problem!

03-03-2008, 01:33 PM
vac hoses are a cheap experiment!

03-03-2008, 02:05 PM
They did a smoke test and found no leaks!

03-03-2008, 03:57 PM
Clean out the throttle body. Take it of the intake manifold and use an old toothbrush and cleaner. I bet there is a carbon ring around it causing it to die when going to idle position. Happens alot on DBW cars. I guarntee that its!!!!!!!

03-03-2008, 04:37 PM
It is actually worn out, so I am going with a new one.I hope it solves the stalling issues for good. Thanks for the suggestion, though :)