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View Full Version : surging idle.

nvno1
08-26-2009, 08:45 AM
Good day folks,

I have done a ton of research and starting to lose it.:banghead::leaving: I figured that i might have to look elsewhere for some ideas as to what could be the cause, as my friend Kent says "sometimes it takes a second set of eyes to help fix the problem" and he has done so. Now that we got the car started the idle is a issue.

Any help would be great and I would love the feedback.

The detail are as such:
87 TII(s4) ecu, motor,tranny, wiring harness, TMIC and walbro 255 fuel pump. Got her to run but she is idling really rough. Boucing from 1000rpm to 1800rpms at a one second pulse. I have checked for vaccum leaks it doesnt appear i have any, my bac is not working i got that disconnected, runs cool (not getting hot), good compression 85psi frnt and rear, good oil pressure, fuel pressure is good, the ecu checks out fine as per testing with FSM sect4. The only think that is weird is the check connectors are not reading showing any response. no volts no nothing.
Rotary#10
08-26-2009, 12:34 PM
did you check your TPS?
nvno1
08-26-2009, 02:19 PM
did you check your TPS?

sure did. that whats so strange? everything seems to be in order.
Phoenix7
08-26-2009, 02:22 PM
have you been taking the UIM on and off? maybe a bad leak after the AFM?
TitaniumTT
08-26-2009, 03:21 PM
85 psi is not good compression. Factory minimum is 88psi.

Regardless, a bouce that big is likely the result of a huge vac leak. Are your secondary butterfly's closed all the way? What are the "hg readings during the bounces?
nvno1
08-28-2009, 07:28 AM
have you been taking the UIM on and off? maybe a bad leak after the AFM?

sorry for the delay in responding i have taken the UIM off twice, however the gasket is new and when i sprayed carb cleaner to check for vac leaks there is no change.
nvno1
08-28-2009, 08:15 AM
85 psi is not good compression. Factory minimum is 88psi.

Regardless, a bouce that big is likely the result of a huge vac leak. Are your secondary butterfly's closed all the way? What are the "hg readings during the bounces?


oh its not good. thanks for the info then. i was under the impression that 80 was the min. i used a regular compression tester with the little valve gone and it was old. the markings on the face were a little hard to read as it jumps from 70psi to 100psi in increments of 30 with smaller marks in between. i will try to get another gauge this weekend. the hg reading are like -5/-7@1000rpm and when she spikes up to like 1800rpms its like -12/-15. i will video the event hopefully today or this weekend.