barkerd427

Ok, so I have made some changes to my 89 951, and now it has a problem.

Everything leading up to problem: To start, the A/C compressor fell off in Ohio on my way to Illinois from NC. I fixed that at Autozone and everything has been fine without it on. I then replaced the stock chip with the ostrich 2.0 that has been discussed on here. Everything seemed to be working well with that on. I then installed a lindsey racing MAF that sends the regular signal to the ostrich. I didn't have a chance to drive it after that was installed, because my fuel rail had developed a leak. I got that taken off and welded. When everything was put back together the car was running really rough and would constantly bog down and I guess go into a limp mode or something. I think that may have just been a loose spark plug wire from me messing around in there, but it still has a problem.

The Problem: Everything is fine up to 4th gear. I can go from idle to red line in all four without any noticeable problems. I then slow down (going to fast on public roads) to about 80 and shift into 5th. Sometimes the car will take off for a second when I go WOT, but then it bogs down and will not recover. After that it doesn't matter what gear I am in, every time I go WOT it will immediately bog down. I have no problems at all with partial throttle in any gear or idle. It idles a little rough, but nothing substantial. Also no starting problems. Also, when it bogs down, I can push the clutch in and it revs fine.

Things I've done or thought of: The first thing I checked were all the connections and the ignition system. Everything looks good there. Next, I replaced the fuel pump and fuel filter and checked to make sure I was getting good flow. Everything was good there. I doubt it is the ostrich 2.0 since I had no probs before, but it may have something to do with the MAF. I dont know why that would matter only in 5th though. My oil press sender is also not sending a signal to my dash gauge, but I doubt that has anything to do with it.

Any help would be greatly appreciated. If you need any more info just ask and I will do my best. I do all of my own work, but I don't think I screwed anything up. Thanks.

KuHL 951

Does it boost normally 1st to 4th? When it bogs down in 5th can you feather it back up to normal or does it just stay like that no matter the throttle position?

User 52121

Well the first thing I would do is try to get it back to the state it was in when it was running well. Undo any changes you've done since then, and then put them back one by one.

So to start, I'd remove the Lindsey MAF, put the stock AFM back in there, and see how it goes. Post the results of that and we can go from there.

barkerd427

It boosts normally for 1-4. After it bogs down in 5th it responds normally to partial throttle input. I will try to get the old AFM in there somehow, but I partially destroyed the J-boot when taking it out. That's the only reason I haven't tried putting it back on yet.

CPR

B,
PM username "JohnKoaWood" affectionately called "Joka". He can help you with this set-up, and is a great guy to work with.

JohnKoaWood

I am here... I would say no worries..but first things first..

What type of instrumentation do you have installed? I.E. WBO2, Data logging, etc..etc..
With Your MAF... is it the LR Quad M?
What tuning software are you using to modify the maps in the ostrich?
are all other components on the car stock? FPR? Injectors? Turbo?
Do you have any way to monitor Knock events?
What boost level are you running?

If running, does it bog down in all gears at WOT, or just 5th? Does 5th gear pull run good at partial throttle?

My first guess is you have vacuum leaks causing both your rough idle (or a poorly adjusted TPS), and bad knock when WOT in 5th (or horrible AFR when WOT...)

Start off by looking for vacuum leaks, then move on to slowly retarding the WOT timing map 3520 RPM and up one step at a time... Knock causes the KLR to pull timing, which WILL make your car feel as if it all of the sudden falls flat on its face...If your TPS is mal-adjusted it is possible that correcting this will fix both your rough idle AND your WOT knock (if the throttle body is wide open, but the TPS is still showing the ECU a partial throttle...)

What AFR are you seeing when it bogs down?

Details on mine are 14.7 idle and cruise AFR, 13:1 partial throttle acceleration, 12:1 WOT, 15PSI boost, Full Zietronix setup (WBO2, EGT, Throttle position, MAF Voltage, RPM and Boost pressure all being recorded), I also have a Curtis knock counter for monitoring knock events, 26-6, Black **** MBC, AM boos gauge, Ostrich V2 and I am using MaxTune for tuning...

Rogue_Ant

Tuning in...
The DME/KLR does not differentiate gears... Whatever the issue is, it happens regardless of gear - 5th gear simply makes it more noticeable.

I'm betting it is an AFR issue. I'll echo John, and ask what AFR you are seeing when it bogs down?


-Rogue

JohnKoaWood

While the DME / KLR don't differentiate between gears, 5th gear does result in the highest load applied to the engine...

AFR and or Timing... have to be causing the Bog, and it is most noticeable in 5th due to gearing / KLR pulling timing...

from the OP description it doesn't sound like he is doing WOT pulls 1-4... but if he did I bet the WOT would result in bogging in all gears...

CPR

maybe he is using an IB server to tune with....

barkerd427

I have nothing installed yet, cause I was waiting until I had the exhaust and everything else torn apart for some more add ons, but I will now be installing a wideband O2, knock sensor, and boost gauge as soon as I get some time.
My MAF is the Lindsey Quad-M. Using TunerPro. Everything on the car is stock except the fuel pump which is the Bosch HV (Installed after problem started) and the intake.

I am going WOT from 1st through 4th. I press the gas to the floor in first and only let up to shift and then it goes right back to the ground. 4th tops out somewhere near 140.

I was thinking it may be due to the extra air that the intake allows, but I won't know until i get the wideband in there. I have thought of the TPS, but haven't checked it yet. I hadn't noticed the rough idle that much until this weekend.

I appreciate the help and ideas. Hopefully I can get some monitoring devices installed over the next couple weeks and figure this out. I just changed almost all of the vaccuum lines so that isn't it unless I accidently left one disco'd. I'll have to look them over again.

I am planning on adding a bigger turbo (K27/8), a 4 inch exhaust, a bigger wastegate, and bigger injectors. Should I just do that and then see if it is still a problem after I tune it?

Also, Rogue, do you happen to have a base map that would work with the setup that I am gonna have? I am just looking for something that will get me close so I can tune it from there. What size injectors do you have? I am thinking 55's will be enough.


Thanks for all the help guys.

User 52121

I think you are changing too many things at once. If you start modifying a car that wasn't running right to begin with, you'll never know what the cause is - your additional mods, or something else. And if you're adding "go fast" parts, you could wind up just exacerbating your problem and even possibly really hurting the motor. (If the root cause of your issue is AFR now - it will only get worse if you add a bigger turbo, bigger exhaust, etc.)

Back up a few steps, figure out a way to rig up your j-boot (or buy a used one off a RL'er), put the AFM back in, and go from there. If it runs right after swapping in the AFM, then it confirms there is nothing else wrong with the rest of the car (fuel delivery, etc.) From there we can then determine if it's a faulty MAF, an incorrect MAF installation, perhaps a fuel/timing map issue, etc.

If you're planning to do gauges eventually, then I'd suggest doing them first. That way you'll also have a good baseline to go from as far as what your car does when it's normal and healthy.

Get it running right first. THEN add more parts. Too many variables right now.

TurboTommy

+1 on triggering limp mode
In 5th gear you'll almost always get an extra psi of boost, and along with the extra load on the engine, the knock sensor is probably triggering limp mode.
Or maybe, you have over boost protection still activated within your engine management system, your right on the cusp with your boost, and 5th gear is hitting it every time.

prossi

sound like its hitting the overboost protection, my car used to do the same thing.

i have a lindsey power perfect for sale so you can tune the AFR

barkerd427

In case anyone cared, I figured out what the problem was. I was running too rich at the higher RPMs. I got my AFR gauge installed and after i adjusted it everything worked fine. Just to test I made my partial throttle too rich and it did the same thing at partial throttle. Thanks for the help guys.

Rock

Youre hitting in knock protection. AKA Overboost.

Once its hit, the car wont be able to boost over ~4psi without the DME cutting it out. The only quick way to reset this is to turn the car off and then back on.

After a time period however, it will reset.