Audi/VW wont rev past 4,500 RPM??? Why???

RSTPerformance

RSTPerformance

New member
Does anyone have any ideas on why my Audi won’t rev past 4,500 RPM without breaking up (sputtering)? I am sick of this car!!!

I have dealt with this issue for over 2 years. The problem comes and goes depending on its mood for the weekend. We will fix something and it will go away, only to come back the next race. Then we will fix something else; again it will go away and come back on another race. Outside temperature does not seem to affect the car although the length of running time does. As a session continues the car gets worse and worse, breaking up more and more at lower and lower RPM’s. If you hit a bump in the past it has dramatically increased the problem. After the car comes in and sits for a half hour to an hour and cools off it will run better again and then progressively get worse as it did in the prior session. I would like to know EVERYTHING that could cause the car to break-up at higher RPM’s.


Thanks for the help…
 
Originally posted by RSTPerformance:
If you hit a bump in the past it has dramatically increased the problem.
Click to expand...

As a wise man (me...) once said: "It's either electrical, or something else."

Bump. Connector problem. Ground problem. Or something. What engine systems can be affected by mechanical shock ? Electrical.

When it's 'bad', can you get a timing light on it to see if it's suddenly got bad spark scatter, or if the spark has gone weak ?

Some combination of temp problems and electrical gremlins ? Is your ECU getting too hot ? What version injection is in the car, and how old are all the sensors (water/cyl head/intake air/fuel mojo/etc.) ?

Try throwing another distributor or ECU at it. Time for a shotgun fix, even if you never figure out which component is bad.

It's either electrical, or something else.

[This message has been edited by JohnRW (edited May 10, 2004).]
 
Somethign else to check. You guys are running the stock tank correct? It could have rust in it and the rust is getting through the fuel filter and clogging up an injector. I have a first hand experience with this see the October 2001 GRM. It cost us a possible chance at winning the 12 Hours at the Point. I ended up replacing the entire fuel distibutor and injector lines. You can also run Coca Cola through the injector lines and injectors to clean them out. Hope this helps

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Sam Rolfe
TBR Motorsports
#85 ITC VW Rabbit
#85 GP Scirocco
 
Ignition module? Under heat and load, I've had them act funny. Only solution is to change it. Second the grounds. You may want to change them to new components as I have seen corrosion wick up a wire. While the connection looks fine, the wire itself is junk. Also, don't you and your brother run identical cars? I'd look at swapping parts from one to the other until the problem was identified (then I wouldn't tell my brother the problem so he could deal with it
wink.gif
). Seriously, if needed, I would swap the entire drivetrain/electrical/fuel until the offending part was identified.
 
Raymond;

Didn't you have an electrical fire in that car late last year? Watkins Glen in October I think?? Others have posted as to electrical and grounding gremlins - and I have to concur that if your wiring has any kind of intermittent short or "leak to ground" then this could cause all kinds of problems with your ignition system - thereby causing "sputtering" etc.

All this being said, what kind of replacements did you do to the wiring AFTER the fire? All?? Just what "looked bad"??

Just a thought - but the wiring having anything to do with the ignition and ECU might still be a problem for you, particularly after the fire?

good luck,

Tim M
 
Raymond,

I had this exact same problem w/ my old ITB A1 GTI. You're running CIS-lambda right? I tried all kinds of things, and finally replaced the O2 sesonr control module (KJet box). Cleared it right up.

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MARRS #25 ITB Rabbit GTI (sold) | MARRS #25 HProd Rabbit
SCCA 279608
 
I just wanted to say thanks for the suggestions... if anyone has any other ideas, feel free to post... For this weekend coming up we have a lot to do. I got a Quaife installed into a new tranny, so that needs to be installed. I need to rebuild the axles with better grease as we are trying to do preventive maintenance as they in the past have created their own DNF's. To try and fix the sputter I will also be changing many other things.

The wiring harness was completely replaced this spring.

Air box: I had an altered air box last year that allowed mass amounts of air (maybe to much?). That will be changed back to "stock." (Stephens’s car does not have this) Can too much air going into the air box create a problem??? Maybe the air is moving the flapper when it shouldn't be?

Fuel pump... We have changed that in the past and problem seemed to go away. If you hammer on mine it causes the car to sputter, maybe this is an issue? although the car does seem to get plenty of fuel.

Coil, as in the past changing this also made the problem go away (maybe something happened to the other one in the fire? as the positive feed wire was burned)

ECU, we have changed that in the past and problems went away.

Distributor, maybe that is the problem?

Cap/wires, just cause who knows, can't hurt. Maybe again that is the problem, although the stuff on it is only 1 year old because we thought maybe that was the problem before.

All grounds and vacume lines will be checked, as the engine and tranny will be pulled so they all will need to be re-attached anyway.

Alternator and battery was replaced last weekend and did not make any improvements, car is charging (although new alternator last week resulted in the car not "chucking the belt." We were hoping that the "chucking of the belt" caused the car to be down on electrical power causing a lack of spark. With last weekends performance this does not seem to be the issue causing the car not to run correctly.

Timing belt will be replaced and a new crank pulley will be put on, we found that my pulley is off of a 5000 motor thus may also be the reason the alternator belt kept falling off. That pulley takes a smaller width alt belt but all else is the same. Wish we had found that before... (The crank pulley was replaced after being damaged in my "off mountain" excursion at MT Washington 2 years ago. When the car was rebuilt it was with the wrong part
frown.gif
(Yes I agree illegal, but everything is the same between the two with exception to the alternator belt size, not sure why they are different??? Anyway ITBer's I hope you don't think my success was a result of that as I think it probably was related to the belt flipping so was a performance disadvantage
wink.gif
) THE ALTERNATE PULLY WAS NOT AN INTENTIONAL SWAP, IT WAS A MISTAKE

The starter needs to be replaced as I crossed the wires last night taking apart my switch panel and the starter seems not to work anymore. (My fault should have disconnected positive feed (turned off switch) before playing with the panel).

The other two components under the dash that are behind the glove bock with the computer will be switched out (are these the O2 sensor control module and Ignition module?) If not where are those???

The fuel injectors and lines... can I put the injector cleaner into the gas??? Is that legal or is it a fuel supplement that I will get bagged for? If the stuff is as good as "coke" then I would rather do that... even if it isn't legal... I would rather race than be watching my mirrors all day at Pocono. How do you do the coke thing, and would Pepsi be ok??? LOL seriously though what’s the deal with that? Pull from the motor and pore the soda through it?

Gas tank... No sediments in clear filter so I don't think that is the problem. The filters don't seem to be clogged at all, and when the car is really running bad you can get it to sputter at an idol by continuously revving the $#!!^ out of it. If I had time or $$$ I would change tank or put in a cell with eroquip lines. The eroquip part of the feed line will be replaced in engine bay as it does have a small "squished spot" although I don't think that it has an effect, otherwise it would be constant, right?

Can anyone think of anything else that should be replaced???


Our biggest problem is the car is not even close to street legal, and their is no place to "test" the car out as we live on a rather well traveled road 24 hours a day that cops visit frequently. It makes our only testing grounds the track...

This is a major task (once again), if my car runs like crap at Pocono don't stop and visit me, I will probably be rather grouchy
wink.gif



Raymond "getting burnt out after 2 races" Blethen
RST Performance Raicng

[This message has been edited by RSTPerformance (edited May 11, 2004).]
 
Raymond,

A couple more suggestions from the "been there and done that" club.

What is the voltage at the fuel pump while the car is running? I had an ITC Scirocco that kept burning up fuel pumps, and it turned out the wiring harness, although it looked fine, had developed corrosion and increased resistance to the power wire to the pump. There was only 7-8 volts at the pump with the car running. Too low, it couldn't cool properly at full power fuel flow, and when it started to fail it would do exactly what your car is doing. When it was cool it would test just fine in the shop. Drove me nuts! Finally changed the wiring to the pump and made sure that it had a good ground and voila! No more burnt up pumps!
biggrin.gif


The airbox shouldn't affect anything. I have a ram-air intake (headlight opening duct completely sealed to the airbox) and no problems.

Ignition problems are a pain in the butt, and hard to detect. My suggestion is to make sure EVERY ground is clean, EVERY power wire to all components is giving a full 12-14V, and use MULTIPLE grounds from the engine block to the frame.

Hope you can get it fixed soon!!

MC

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Mark Coffin
#14 GP BSI Racing/Airborn Coatings/The Shop VW
Scirocco
Zephyr Race Coaching and Consulting
http://pages.prodigy.net/Scirocco14gp
 
Raymond,
Pepsi will work like coke(thats what we used at Summit) I wouldn't recommend putting it into the tank
smile.gif
We found that the problem was coming after the fuel distributor so what we did is disconected the injector lines and and ran cake through them. It worked excellent. Good luck on getting the car together.


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Sam Rolfe
TBR Motorsports
#85 ITC VW Rabbit
#85 GP Scirocco
 
Originally posted by SamITC85:
Somethign else to check. You guys are running the stock tank correct? It could have rust in it and the rust is getting through the fuel filter and clogging up an injector. I ended up replacing the entire fuel distibutor and injector lines. You can also run Coca Cola through the injector lines and injectors to clean them out. Hope this helps

Click to expand...

ahhh the memories



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Doug :)
NER.org
the16v.com
briansgarage.com
 
Originally posted by 16v:
ahhh the memories
Click to expand...

I will say this about that weekend I never had more fun at race even though I had to come in the pits every 30 minutes or so for a new injector. Although I do wish we had Brian's conversation about Yury on tape. "Was the radio on push to talk, or talk to talk? Oops well I guess he heard that huh?" Maybe we can do it again next year, but with 4 injectors that work. We just need to make sure that there are no tire wals close enough for brian to end up on.
By the way can you either email me the pics from that weekend. i lost them. Also if you still have an archive of video and pics from the Cheap Date Weekend from 2001.

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Sam Rolfe
TBR Motorsports
#85 ITC VW Rabbit
#85 GP Scirocco

[This message has been edited by SamITC85 (edited May 12, 2004).]
 
Raymond,

I remember discussing this problem with you guys at the track a few years ago. I still believe that it *IS* a fuel pressure problem (at the injectors). It's probably related to the frequency valve on the CIS-lambda fuel distributor that increases the control pressure (thus reducing injector pressure). IMHO, the frequency valve should be disabled on these cars (either using a suitable fixed-orifice restrictor or doing more involved replumbing), especially since it can't read the O2 after a tank of race fuel anyway. As a quick check, try running a pre-emissions CIS-basic fuel distributor (up to 1980?) just to see if the problem goes away, and if so, bite the bullet and do the mod on yours. Another option, depending on the model year listing in the ITCS, would be to run the CIS-E fuel distributor (1984-up?), which can work with or without electricity!

-Eric


[This message has been edited by Eric Parham (edited May 12, 2004).]
 
>>related to the frequency valve on the CIS-lambda fuel distributor that increases the control pressure

This is what I was trying to say at Pocono. But I thought your car was CIS not CIS-E so I didn't mention the freq valve. From the sound of it in the pits I'd say it's NOT electrical. Eric's guess is my guess.

Best of luck to you and hope to see you at WGI ...with 2 cars. Don't give up.


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Bill Sulouff - Bildon Motorsport
Volkswagen Racing Equipment
## 2003 ITB NYSRRC Champs ##
 
A while back, my 83 GTI wouldn't rev over 5500rpm with any authority. I finally replaced the ignition coil and that solved the problem.
 
get the car to my shop with a pass seat and muffler; loan me the title; I guarantee you to solve the problem in relatively short order. phil
 
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