1G Full Throttle Problem

[Dsmpagan]

Hi. I'm starting my car up after a rebuild and having a problem. When I turn on the car it jumps to full throttle and wont come down. I checked the throttle cable and its fine. I did change the TPS. I swapped my head from my 1990 to my 1991. The TPS connection was different so I took the TPS off the 1991 and put it on the 1990 head so I could plug in the cable. Could that be causing the problem. Any other thoughts or suggestions would be helpful.
Thanks
Pagan

 

[2gmitsueclipse]

sorry i updated my profile

You can create a profile for your DSM by moving your cursor to the DSM Profile tab at the top of the main page. A drop-down menu will now show. Select "Create DSM Profile". The direction from there will be self-evident. I am recommending this to merely let other members know what you are working with to help provide advice. I had assumed that this was a fairly stock vehicle based on your first few posts. The more detailed you are, the less repeated questions about your setup will be asked of members trying to help you out.

 

[kjlinwi]

Off the top, throtpos should not be 49% and cool temp should not be -74F. default if you disconnect the sensor should be -40F.

Don't go off chasing these just yet. Stay focused on the problem. Couldn't tell you how many techs get lost in the woods chasing all the little data anomaly birdies. Stay on point with the problem.

As far as should or would be, assume nothing. Make sure your throttle plate is staying closed and not flopping open. Sounds like you didn't block off the ISC passages either.

If you make assumptions, then it will just take longer to diagnose what's wrong. Block the ISC passages after you make sure the throttle isnt flopping open and let me know what happens.

 

[Dsmpagan]

Here is my set up so no one has to look. 1991 Eagle. buschur racing stage 3 head, 272 hks cams, precision 850 injectors, magnus intake, upgraded throttle body not sure which one bought it ages ago. coil on plug. FP 3065 turbo, 3inch exhaust, tubular exhuast mani. ECMlink v3. Basic story is bought a 90 back in 2000, blew the tranny. Let it sit for 10 years and it rotted out so i bought a 91 and used the 90 as a donor and moved all parts over to the 91. Sorry to create any confusion.

 

[2gmitsueclipse]

Well, when you get time, feel free to create a profile so you don't have to list everything out when you post a thread. This does provide good information.

Back on topic.

You have completed a boost leak test. What PSI did you test to?
High idle is typically caused by a vacuum/boost leak right at or after the throttle body. You may be able to just do an additional BLT at the tb inlet. Making sure to have warm-soapy water to test with.

Does your TB have the FIAV provision?

If you have coolant passages for it removed, it should be blocked off or bypassed. I think kjlinwi was referring to this also. Without coolant running to the throttle body the FIAV won't shut when the car warms up resulting in too much air bypassing the throttle plate, which can cause idle and stalling issues. The solution is to adjust the FIAV so that it's always closed.

 

[Dsmpagan]

What does the FIAV look like? I know I dont have coolant running to the throttle body because i rerouted it when I put the thermostat housing on.

 

[2gmitsueclipse]

http://www.dsmtuners.com/threads/fiav-adjustment-disable.320951/

 

[Dsmpagan]

ok thank for the link i will look at it tomrrow after work. My question is i had this set up working fine before i swapped everything over to this new car. Wouldnt this have had to be done on the car before to make it work because it ran fine before i took everything out.

 

[2gmitsueclipse]

I am still leaning towards a leak somewhere at, or after the TB.
Have you also tested the ISC?
When is the last time the ECU was serviced?

If the ISC is being over driven by the ECU because of a vacuum leak the ECU can be damaged. Another possibility is a bad ISC, which could cause idle problems, and damage your ECU.
http://www.ecmtuning.com/wiki/driver01

 

[Dsmpagan]

i have the ISC off the other car should i try swapping it out?

 

[Dsmpagan]

Great news. I pulled off the elbow going to the throttle body to look at the butterfly and it was half open.

I had tightened the throttle body cable too much causing the throttle to be about half open all the time. Just like ECMLink said, the throtpos was at 49%.

Now I'm not sure if this solved the problem because the car has a dead battery, so I will let everyone know tomorrow and maybe tomorrow we can start figuring out why my tach doesn't work. Haha