dvs4eva

Bought the car last week ran great, took it in for an alarm... picked it up, now running like a$$. The car bucks once the throttle is opened enough to produce boost over 1 bar. If parked and throttle opened fully tachs to 4500 RPM and then cuts in and out like a rev limiter would. Def. not missing, runs smooth until boost exceeds 1 bar. Could this be a vacuum problem? hopefully a quick fix. HELP! don't want to have to bring her into the shop.

rocket951

Sounds like you are over-boosting. The DME will go into overboost protection mode and it will buck and lurch at higher boost levels until you shut off the car to reset the DME. Likely culprit is the cycling valve which is located under the intake manifold, the nipples that the vacuum lines attach to get brittle and break off. Replace a broken cycling valve with some other form of boost controller, like a manual boost controller from Lindsey Racing, for example.

Hope this helps.

Rodney

dvs4eva

I will check that out tonight. One other thing, the car will also barely run now when it is cold and blow out smoke (raw fuel), this is all new since I had the alarm installed. Is it likely that the installation shop is responsible? or is it just a coincidenece (in your opinion)

David Floyd

Sounds like a vacuum hose was messed up (torn, ripped, cracked, knocked loose) during your alarm install

dvs4eva

Any recommendations for a manual boost controller and a new set of vacuum lines? type? place to get em?

dvs4eva

A broken vacuum line would be enough to make the car buck wildly when boosting?

David Floyd

www.boostsciences.com

Do a search for vacuum line kits, several sponsors offer kits

Check you car to see if one of the larger turbo hoses was knock loose.

David Floyd

Yes, and if you are going by the stock gauge, the 1 bar is just atomosphere pressure, boost starts after the 1, so if you are at the 2, that is 1 bar boost.

dvs4eva

I have read something about a KLR box, when the line is broken off the DME thinks it is always overboosting causing the shutoff and on (rev limiter like), that make some sense since they were taking apart the underside of the dash for the alarm install, apparently the box is located in the passenger footwell? can anyone confirm?

David Floyd

That is correct, pull down carpet, there will be a clear hard line running into the KLR box,that is the boost line

dvs4eva

Ok checked the line to the KLR, no leaks and the gauge reads properly so the problem must be somewhere else. Which vacuum line if broken or knocked off would cause these symptoms:

Idling really low (sometimes)
Runnning terribly rich
Once WOT or boost gauge reads 1.2 BAR the car sputters like the ignition is turned off(bucking, prob overboost protection)

Keep in mind that the car ran great, full boost, no problems until the alarm installation, I am hoping that someone would be able to tell me which line specifically may have a problem so I can temporarily fix it until the lines I ordered from Lindsey arrive.

Thanks!

P.S. Can anyone reccomend a good set of wires? and a place to order them from.

Ski

Take the car back to where you had the alarm installed, find out exactly WHERE they were during the install, start there. If they were under the hood by the battery or anywhere on the fire wall, there are several lines there that if still original, are very hard and brittle.

dvs4eva

are there any line running under the plastic cowl between the windshield and the firewall? The problem is that they were all over, in the battery compartment and through the looming across the firewall, what should the vacuum read @ idle? 18lbs?

Ski

warmed up, if all good, 17-19 inches of mercury

special tool

What is warm idle speed?