I have a turbo car that starts fine and idles. It is idling right at 14.7 on the wideband. When you try to rev the engine it leans out and wont rev. It has 44 lbs. of fuel pressure. I believe it is in the electrics of the car. Does anyone have any idea of what could be causing this? Thanks guys.

 

Check the TPS.
http://www.clarks-garage.com/shop-manual/fuel-06.htm

 

Thanks Brian. Just downloaded it and going to check.

 

According to the ohm meter and the tests from Clarks garage the TPS is fine. Any other ideas guys?

 

Check the plugs to a AFM and the TPS. What is the vacuum at idle?

 

I know from experience that if the AFM is unhooked, has bad wires, the barn door is stuck, or its dead this will happen. Basically when you crack the throttle the door should swing open richening the mixture.

Clarks garage has a nice testing process for the AFM but its a bit more work than the TPS.

 

So are you saying the the car will not rev past idle? If you think it's "in the electrics", then check the electrics, then report your findings.

Have you checked anything yet? If so, what?

Does the car idle at 14.7afr warm or cold? It could be the fuel pressure, could be the AFM, could be the spark plugs, could be almost anything. Be specific and you'll get more successful tips.

 

It does not rev past idle. It is idling at 14.7 cold or warm from letting it idle for a while. I have a new high volume fuel pump just installed yesterday and the fuel pressure is at 44 lbs. That did not change the problem. The AFM is a DBX from Lindsey Racing and they had me check the yellow wire. It was .5 vdc at idle and goes up as air is passed thru the body of it till it goes to 4.9 vdc. They said that was correct and it was working. I have taken the plug off the AFM and it changed the problem a little. Idles really rough then. I will get a vaccum gauge today and check the vaccum at idle. I am no rocket scientist with the electrical type stuff and really appreciate anything you guys think should be checked. I am just learning how all the DEM and KLR and AFM and TPS work together to control the mixture and all. Can a signal be checked at the injectors to see if they are being told to open? I am not sure if this matters but it has 55lb. Siemens injectors and a super 53 turbo.

 

I also switched from a LR 3 bar fpr to an adjustable regulator. Set it at 44 lbs. with the vaccum line disconected. Just trying to eliminate that as a culprit. Kept thinking it was fuel related because it was leaning out. A new hv pump and regulator did nothing to change it. That is what has me thinking it is on the electrics side.

 

That is a lot of changes that can each could cause an issue. What chips did you get to support the 3 bar fuel pressure and the 55 lb injectors? Also, you should try to change the FQS and see if that make any difference. If the map is wrong for the injectors, it will run really bad or just not start.
Q tip with the cotton removed or a golf tee work well for turning the switch.
http://www.lindseyracing.com/LR/Parts/DMEFQSSWITCH.html

 

The car has been running fine for months. This all happened last week. Now I have been changing and checking things one by one to try and find the problem. I will check the fqs now. The chips are the ones that were purchased from LR for all the other stuff.

 

Did you change anything before it started this problem? The FQS will let you go lean and rich to see which way it runs better if it is a AFR problem. You might also want to do a quick check of your timing marks.

 

^^^Hmmm, doesn't seem like the timing would be off if the car idles fine, but then again, it's too easy to just check anyways.

Check your spark plugs, fuel filter, ignition hardware, etc. lately? What happens to the fuel pressure when you add throttle?

Edit: Just read you're going lean; have you checked the O2 sensor?

 

I doubt it is timing but best to rule it out as it is easy to check. Fuel and air leaks would be the next thing on the list.

Spark
Timing electrical and mechanical
Fuel and AFR

 

Thanks guys. We got it. It was a bad MAF program. One of the unused 10 settings. Not sure how it got changed but sure drove me nuts. Need to check things better. Its always the obvious I guess.