Stuttering on acceleration

Born2bwild1191 · 08-11-2010, 01:23 PM

My car is an 87, completely stock except for 951MAX chips. Immediately after I installed the chips, my car started stuttering under acceleration. It only happens when I haven't driven the car for a few hours, and after about 20 mins it stops. It happens every single time I get in full boost from 4k to 5k rpms. It backfires and blows black smoke out of the tailpipe. After about 20 mins of driving, it runs perfect. People have told me it just needs to warm up, but I know this cannot be normal as it never took anywhere near this long to warm up before I installed the chips. Anyone have any ideas? I cant get into boost on the way to work

Thanks guys!

running_cold924 · running_cold924's Garage

are you 100% sure it goes away with the stock chips re-installed? if so, i'd say something is up with the chips...

Born2bwild1191 · 08-11-2010, 07:07 PM

Well, i never re-installed them, because the Lindsey ones are still awesome after 20 mins of driving. It never did this before the chips, that's all. The car is totally drivable, just irritating. Usually after I shut it off when I get to work I'm good for the rest of the day with no problems. I called Lindsey today and left my number, awaiting a call back to talk to them.

rberry951 · 08-11-2010, 07:14 PM

It sounds like the 951MAX chips you have may be designed for a different vehicle. Where did you get them? Lindsey Racing sells MAXhpkit chips, which is why they are labeld LR/951MAX on their labels. Chips that come directly from MAXhpkit (me) are labeled with MAXhpkit logo.

Now when you say the car is completely stock except for the chips, do you have a 3.0 bar fuel pressure regulator installed, and/or a manual boost controller of some sort?

Regards,
Russell

minho78 · minho78's Garage

Quote:

Originally Posted by rberry951

It sounds like the 951MAX chips you have may be designed for a different vehicle. Where did you get them? Lindsey Racing sells MAXhpkit chips, which is why they are labeld LR/951MAX on their labels. Chips that come directly from MAXhpkit (me) are labeled with MAXhpkit logo.

Now when you say the car is completely stock except for the chips, do you have a 3.0 bar fuel pressure regulator installed, and/or a manual boost controller of some sort?

Regards,
Russell

Russell good to see you arround. What about TPS?

running_cold924 · running_cold924's Garage

i think if it ws tps, it would be all the time. maybe something warm up related? like O2 or temp sensor map missing/not right

minho78 · minho78's Garage

Quote:

Originally Posted by running_cold924

i think if it ws tps, it would be all the time. maybe something warm up related? like O2 or temp sensor map missing/not right

Mine used to do it at arround 2k it would miss and i would have to bring the car up with a couple of Rev/misses. Once it was warm it would be fine. Also clean the Throtle body. Test the tps at the test port, and then go from there.

rberry951 · 08-12-2010, 09:38 AM

Quote:

Originally Posted by minho78

Russell good to see you arround. What about TPS?

Oh I'm around, just been busy working the regular job doing computer stuff. I'm actually getting geared up for a track tour next summer.

I agree, if the tps was the issue, it would probably be consistent with any chips. Make sure your FQS switch is set to zero, fully counter clockwise, make sure your FPR is good, and of course the biggest culprit most of the time in these cars are vacuum/boost leaks. Get a regular analog boost gauge which shows vacuum as well and see how many Hg your are pulling at idle. And how much that vacuum fluctuates.

Many things it could be, you need to go through some troubleshooting steps. If you have a call into Lindsey, I'm sure they'll get back to you soon.

Born2bwild1191 · 08-12-2010, 11:35 AM

I got them straight from Lindsey, I do not have a 3 bar FPR or MBC.

What is the TPS and FQS switch?

968 GUY · 968 GUY's Garage

Ouch!
Throttle Position Switch
Fuel Quality Switch.
If I'm not mistaken, Lindsey has a tech section explaining the FQS, maybe the TPS.

89-944NA · 89-944NA's Garage

I stutter when I drink to much

Born2bwild1191 · 08-13-2010, 04:29 PM

Ironically enough, I think that's exactly why my car is stuttering....drinking too much fuel

89-944NA · 89-944NA's Garage

I know some stuff in a green bottle that comes from latrobe....makes me stutter when I consume to much

Yes, I have a one track mind today, it's 5:30pm Friday, and I'm in for the evening....time to get ready to do some serious stuttering as me and the boys play Texas Hold'em.

Born2bwild1191 · 08-13-2010, 06:32 PM

Texas Hold em is a fun game, and Rolling Rock doesn't come from Latrobe anymore

They moved to NJ i think a few years back

89-944NA · 89-944NA's Garage

No wonder it tastes like swamp water now. lol

Born2bwild1191 · 08-14-2010, 12:10 PM

Well I think my problem is fixed....Two hose clamps were incredibly loose: The big hose going into the throttle body, and the fuel dampener. The hose clamp on the big hose actually broke off when i tried to tighten it and the hose on the damepener was actually falling off and fuel was seeping out. I fixed these and took it out for a ride, so far so good

rberry951 · 08-14-2010, 12:38 PM

Quote:

Originally Posted by Born2bwild1191

Well I think my problem is fixed....Two hose clamps were incredibly loose: The big hose going into the throttle body, and the fuel dampener. The hose clamp on the big hose actually broke off when i tried to tighten it and the hose on the damepener was actually falling off and fuel was seeping out. I fixed these and took it out for a ride, so far so good

Hang on, this is not good. First, are you talking about the damper or the regulator? Damper is on the front of the fuel rail, regulator is on the rear referenced from the front of the car.

But if you have fuel coming out of either, it means the membrane is bad in the device and you need to NOT drive the car. Fuel leaking directly over the exhaust of a turbo car has claimed many cars in fire.

It sounds like the car needs a good going over. You should reach out to local Porsche guys in your area, kick back a few and let them poke around under the hood and tell you all the nastiness to watch for on these cars. The biggest mistake you can make on any of these cars is lack of maintenance. When well kept they are damn near bulletproof. But let them go, and you are in for a slow ride to bankruptcy...

Good luck!

Regards,
Russell

Born2bwild1191 · 08-14-2010, 07:59 PM

Im aware of these things. I know what lack of maintenance means on them and I know what I'm doing 99% of the time. Before I bought the car it sat for about a year. I go over it often to check for simple things like this which is how I caught it. It was the damper, not the regulator. The line was almost falling off which was why about a drop of gas seeped out when I pushed it back on. The fuel was not actually coming out of the damper, it was coming out of the fuel line. I realize that via internet posts you can't tell a person's enthusiasm or intelligence about something, but I'm under the hood of my car constantly and I'm as proactive in the maintenance as possible.

rberry951 · 08-15-2010, 09:27 AM

Quote:

Originally Posted by Born2bwild1191

Im aware of these things. I know what lack of maintenance means on them and I know what I'm doing 99% of the time. Before I bought the car it sat for about a year. I go over it often to check for simple things like this which is how I caught it. It was the damper, not the regulator. The line was almost falling off which was why about a drop of gas seeped out when I pushed it back on. The fuel was not actually coming out of the damper, it was coming out of the fuel line. I realize that via internet posts you can't tell a person's enthusiasm or intelligence about something, but I'm under the hood of my car constantly and I'm as proactive in the maintenance as possible.

I wasn't trying to imply that you don't know what you're doing. I make no assumptions about what anyone knows or doesn't know. I only know what you tell me, and yes, much does get lost in electronic communication, which is why I always suggest getting together with some fellow enthusiasts and going over the cars together, share knowledge, and just have a good time.

The 951MAX DME III ships all require a 3.0 bar FPR. I also make a DME I 'Booster' chip for a completely stock car, including stock FPR. If you bought one of the DME 1 chips, you should be fine. But if you have the DME III, you need a 3.0 bar FPR. They are also designed for higher than stock boost, which requires some sort of manual/electronic boost controller. Maybe I'm just missing it, but I don't see the DME 1 chip anywhere on Lindsey's site. Find out for sure which you have because if you have the DME III using the stock FPR you are probably running too lean.

Regards,
Russell

Born2bwild1191 · 08-17-2010, 05:44 AM

Sorry, I guess i took that wrong

INstead of the 3.0 bar FPR, an adjustable FPR would work, right? I'll probably just do that if that would work. I ordered the chips from a local Porsche guy that is a Lindsey dealer (HRE). I told him my setup, and he ordered them from Lindsey so I'm not 100% sure on what he actually ordered. I'm going to have to call him to find out, but I would rather have an adjustable FPR anyhow I think...