RajDatta

Decided to yank both the dme and klr and send them to ecudoctors. More to follow..

Crazy Eddie

Hey Raj
I feel for ya bud ... Your cars a beautiful, and I understand you want the best but couldn't you get someone to loan ya a KLR box?
Jeezz that's a lot of $'s to spend on a hunch ?
I can't help but think of this, when I see ya doing that ....
I hope it works out for you, and it solves your problem. I didn't have a spare box otherwise I would have offered ...
Best regards
Ed

RajDatta

Ed, no worries. I am used to not getting much help here since I don't own a 951. Fortunately, there are still a few that are always willing to help.

I have limited time due to family and work requirements. Since the ECU's are old, I rather service them now and eliminate that as a possibility for the future. Got too much in it to cringe at a few $$. Love the clip, lol.

Thanks for your offer.

Crazy Eddie

I hope it works out...
Always love that video ...
Being the cheap bast@#$ I am, I throw nickles around like they are manhole covers..
Good luck
Regards
Ed

RajDatta

Update:4/6/2013

Recieved both the DME and KLR back from ECUDoctor. They found the KLR to be faulty and rebuilt both units. Put everything back together, still no movement on the boost guage. Drove the car for around 20 mins and all of a sudden had a high idle (around 4K). Took the car back home, tried to make a few adjustments to the cable/tps/return spring/throttle stop etc. I no longer hear the click on the TPS no matter what I do. I can turn the TPS all the way back to lower the idle but then the idle hunting begins.

Removed the throttle body hose and took and look and did not see anything stopping the throttle from completely closing. I get a feeling the TPS is toast and plan to order a new one.

Let me know if anyone has any other ideas.

Ski

sorry to hear that. I have a new connector, new IAS, new vac lines, new venturi delete hoses but, i've got to finish the track car before messing with Blacky. i've got spare KLR's and DME's to mess with if it comes to that. good luck.

Tom M'Guinn

The TPS has two functions. First, it tells the KLR how far open the throttle is, so that the KLR can trigger the full throttle maps. That's probably not relevant here. Second, and more importantly, it tells the DME whether the throttle is (a) closed, or (b) not closed. The click you hear when you crack the throttle open is the little switch inside the TPS changing the state so the DME knows if the car is at idle or not.

The other important thing to know is that the DME shuts off the injectors when the throttle is closed and the RPMs are over about 1600 rpms. When you are crusing at 3500rpms, for example, and then let off the gas for a stop sign, the DME sees that the throttle is closed and shuts off the injectors until the rpms drop down to about 1600. Because of this, when the idle switch in the TPS is working and adjusted properly, the car cannot idle above about 1600 rpms. If you have a vacuum leak or other problem that makes the motor run too fast, the rpms will climb up until they reach 1600, and then the DME will shut off the injectors as described above. Since the injectors are shut off, the rpms drop. As the rpms drop below 1600, the injectors come back on and the rpms climb up again. The result is a motor that surges up and down repeatedly.

In your situation, it sounds like you adjusted the TPS to the point that the switch is not opening correctly, such that the idle is able to go as high as it wants -- in your case 4k rpms. If the idle is going all the way up to 4k, then two things must be true:1) the idle switch in the TPS isn't adjusted or working right (assuming the DME/harness is fine) since it should bounce over and under 1600 rpms, and 2) the motor is getting more air than it should at idle, since 4k rpms requires more air than a closed idle circuit allows.

It sounds like you can adjust the TPS to induce a bouncing idle, which probably means the TPS is working fine and the source of the issue is elsewhere. Where? I dunno, but would start with that J-Boot if you've noticed the idle changing when you poked at it...

RajDatta

Thanks Tom, I had a chance to dig around a bit further and found that the throttle stop switch locknut had come loose, which could have been the potential cause of high idle. Also, I found the TPS to be somewhat inconsistent. At times when rotating to clock, it would click and at times it would not. I have been able to readjust the switch again to make it click when slightly open and when closing. This should address the high idle issue as at the time of high idle, the TPS was not clicking right on/off throttle.

I also removed the airbox to troubleshoot the J-boot issue and see if I still have the same symptoms.

I should be able to free up a bit today to dig in deeper. In the meantime, I plan to get a new TPS, new temp sensors and new O2 sensor. If nothing else, its good to have a new set for troubleshooting. My feeling is that the TPS is shady. This is not to say I might not be having other issues. More to come..

Thanks for all your help.

Regards,

RajDatta

Argh!! This is frustrating!!

Started the car this morning after TPS adjustment and it runs super rich for a bit and then starts fluctuating. It the past it would smooth out after 30 secs or so. Not anymore. Now it keeps fluctuating at idle like it did prior to me swapping my old ISV.

Nothing has changed between yesterday and today except the TPS was removed and then put back on. Currently the TPS is clicking but now the idle does not stabilize.

To test the J boot problem, I tried moving the J boot around and did not get fluctuations at all. I think whatever the J boot issue was, has been resolved. I swapped the TB hose yesterday, not sure if this helped.

This is looking more and more like a TPS issue. I disconnected the TPS and the idle went really high, which was what happened yesterday while driving. So the sysmptoms from yesterday are similar to when the TPS is disconnected. Enough of this witchcraft, on to a new TPS.

Laust Pedersen

So I took some time to change the KLR (ref post #40) and thought for a moment that solved the cold idle hunting, until I went through the necessary idle adjustment procedure ... same story (no solder cracks visible in either unit).

Next attempt will be to replace the speed and reference sensor connectors, which are in a ridiculous condition (cracked and held together with wires).
I managed to find substitute connectors here and here. OE connectors are nice, but at $80 vs. $10 I think I can live with non-stock connectors.

Laust

Tom M'Guinn

Sorry it's still a pain. Why do you say it is running "rich" -- how do you know that without a wideband? Regardless, the motor should not run at 4k just because the TPS is unplugged, so something else is causing that. Connecting the TPS is triggering the injectors to shut off as I describe above, so if anything your results are suggesting the TPS is good not bad. A vacuum leak near the FPR can increase fuel pressure. The hose on the FPR normally has a nice vacuum which reduces the fuel pressure at idle. If the hose has a poor vacuum, the fuel pressure will be higher than you want and the car will run rich. Test with a vacuum gauge on that hose or a fuel pressure gauge. Not sure what MAF you have, but you should also check the idle voltage on pin 7 of the DME to see if the MAF is reading too high causing it to be rich. Did you confirm the FQS settings before reinstalling the DME? Temp sensors are very easy to test with a multimeter. If you need help with that, just say. O2 sensor can be the cause of richness, but easy enough to test be just disconnecting the connector at the back of the intake manifold. I'm wondering if there are any rennlisters or mechanics around you that can help you run these kinds of diagnostic tests? While it doesn't hurt to put new parts on the car (who doesn't like shiny new parts) it seems a low probability/high frustration way of finding the problem...

RajDatta

Thanks Tom, I did exactly that. I disconnected the O2 sensor when soot was initially shooting out the back. In the past when I would disconnect the TPS, the idle would stabilize at 1600rpm, which is not the case now, so you might be on to something. There is something else that is causing the higher idle speeds.
I have the scivision maf setup. I did not install it myself but had the dyno shop install it so I have no relevent history to go with. Not sure what FQS settings were done at the time but since the DME and KLR are easily accessible, I can check to see what the current settings are.
My harness is brand new and so are the speed and reference sensors. I plan to pick up a digital voltmeter today to finally start reading values.
Just got back from a drive and no high idle. Idle is still hunting but the high idle is gone. I only drove for 10 mins so far. Yesterday, I had been driving for a bit before the high idle happened.

Tom M'Guinn

Wet soot on cold start up is pretty normal -- it is the condensation mixed with carbon crud in the exhaust pipes. Think of it as a steam cleaning for the inside of the pipes. Doesn't really suggest it's rich. It's not really possible to confirm AFR's based on the appearance of the exhaust, though obvious black smoke and gas-rich smell can tip off the experienced eyes/nose. Glad to hear you're getting a digital multimeter -- that's the way to go. Look for one that is self-ranging so you don't have to fiddle with ranges. If you have a chance to take a video of the hunting idle, that might help. I presume it is cycling up and down as the injectors shut off and on, but video would help confirm that. Might get a vacuum gauge while your shopping, as it's worth checking the vacuum level at the FPR port. I still suspect air is getting in somewhere.

black944 turbo

Hey Raj,

Have you pressurized the intake side yet? This really should be one of the first things you should do. As Tom has said sounds like a vacuume leak or boost leak.

RajDatta

On the todo list for this week.

Thank you sir!