- Dec 1, 2004
- 31
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been having a high idle problem with mustang. at first sounded like a big vacuum leak but after doing the basic checks i couldn't find one. so this is the break down of the setup and what i have done.
So this is my setup
88 mustang with a 95 cobra engine. (I purchased a running 95 cobra for suspension and ended up using the engine as well.)
I did swap out a mystery cam it had with a tfs1.
I did the mass air swap using a9p.(I converted car from aod to t5)
Now before the engine swap the car was running normal. I did notice was that from time to time it would rev up by itself when I would depress the clutch when I was in parking. It only did it a handful of times. And the other was that after I would drive it for a while it wouldn’t want to crank over anymore.. I would to have to wait till it cooled down. (Possible a bad tfi module)
Initially I was just going to put the gt40 heads/rockers/ trick flow intake and put it in my block but since the cobra was running and idling fine when I removed it I decided to save some time and do the swap. Since my oem engine was extremely dirty from previous owner not changing gaskets. I prepped the cobra engine to fit my fox setup. Pretty much changed out the timing chain housing/balancer to fox version. I also intake was removed to see the condition of valley. So brand new gaskets where installed when I put engine in car. 24lb injectors/matching c/l
Finally I can get to the problem.
When I turn on the car the car will rev up to 2000 rpm and within a couple of seconds it will gradually climb up to 2800rpm. And within a minute or 2 the header are cherry red hot. Now I tried several things while trying to trouble shoot it.
I know this was very long but I wanted to put everything out there since I have been fighting this issue for the past 4 week on and off when I have a chance after work.
any advice things that i have done or not done will be greatly appreciated.
So this is my setup
88 mustang with a 95 cobra engine. (I purchased a running 95 cobra for suspension and ended up using the engine as well.)
I did swap out a mystery cam it had with a tfs1.
I did the mass air swap using a9p.(I converted car from aod to t5)
Now before the engine swap the car was running normal. I did notice was that from time to time it would rev up by itself when I would depress the clutch when I was in parking. It only did it a handful of times. And the other was that after I would drive it for a while it wouldn’t want to crank over anymore.. I would to have to wait till it cooled down. (Possible a bad tfi module)
Initially I was just going to put the gt40 heads/rockers/ trick flow intake and put it in my block but since the cobra was running and idling fine when I removed it I decided to save some time and do the swap. Since my oem engine was extremely dirty from previous owner not changing gaskets. I prepped the cobra engine to fit my fox setup. Pretty much changed out the timing chain housing/balancer to fox version. I also intake was removed to see the condition of valley. So brand new gaskets where installed when I put engine in car. 24lb injectors/matching c/l
Finally I can get to the problem.
When I turn on the car the car will rev up to 2000 rpm and within a couple of seconds it will gradually climb up to 2800rpm. And within a minute or 2 the header are cherry red hot. Now I tried several things while trying to trouble shoot it.
- Tps. I tried to adjust tps but I only had a range of .53-.64 on signal wire (green) 4.95 volts on orange wire and I was using black wire for my ground. I swapped it with another spare tps and it gave me same numbers. At that point I went to store and bought a brand new one. And that one gave me same numbers as well.. which came to conclusion that tps was fine. I also checked the 5 volt reference on the sensors that are in line and they all checked out. I even checked the tps signal wire at the computer and still got .64 volts koeo.
- Iac has been cleaned out/while engine is on and revved up it has no change on idle.
- Mass air meter. While revved up I can disconnect mass air meter and car will idle down to about 800-950 and when I rev it up it take a long time to idle back down.
- Timing. All this time the car was set to 10-11 degrees of timing. Now with everything connected as it should I went ahead and retarded timing because I notice that when I would it would idle down. I was able to get it to idle at 800 rpm but the timing was at -12 (balancer goes up to -10 and it was a bit after that). The down side is that the header still seem to be getting red hot and when I rev it up it’s not very responsive.
- I swapped computer to an a9L and had same results
- I cleaned out salt and pepper shakers and same results
- I swapped out the main harness/injectors harness from 92 gt with factory mass air and still had same results.
- Remember I mentioned about mystery cam.. well since I didn’t know what cam was in cobra engine or how it was installed that’s when I opened it up and swap that mystery came with tfs1 that I had. While in process I swapped out to different intake and same results.
- And before most of those things where swapped out the sprayed car with brake cleaner to see if I can find a vacuum leak and I didn’t have any luck. I even went as far as plugging up all the vacuum ports but had same results.
- I even swapped out intakes with new gaskets with same results.
- swaped out to another 24lb maf same results (i even went back to 19lbs injectors/ stock maf with same results)
I know this was very long but I wanted to put everything out there since I have been fighting this issue for the past 4 week on and off when I have a chance after work.
any advice things that i have done or not done will be greatly appreciated.