Speed density wiring issue (solved)
Thread Starter
Joined: Mar 2000
Posts: 5,703
Likes: 132
From: Orange, CA
Car: '90 Trans Am-12.45@110.71
Engine: 355 w/AFR 195's Elem. 400/430 HP/TQ
Transmission: Tremec T-56
Axle/Gears: 12 Bolt 3.73
Speed density wiring issue (solved)
I am going to throw this out there in case anyone else has had the problem.
I am working on a '91 SD harness. (730 ECM)
The problem..... the ECM does not turn on the primary fan.
The temp control is set at 190* even at 220* the fan does not turn on.
I ground the wire at the "E" 8 terminal on the ECM connector and the fan comes on but the ECM won't turn it on. (so the relay is good)
I have checked all the grounds at the ECM connectors that connect at the back of the heads and they are all good.
Also, the 02 sensor reading is not right and when I open the throttle the engine pops and bangs. It runs ok at idle and 3000 rpms
I must be missing something somewhere.
Any help?
Thanks
I am working on a '91 SD harness. (730 ECM)
The problem..... the ECM does not turn on the primary fan.
The temp control is set at 190* even at 220* the fan does not turn on.
I ground the wire at the "E" 8 terminal on the ECM connector and the fan comes on but the ECM won't turn it on. (so the relay is good)
I have checked all the grounds at the ECM connectors that connect at the back of the heads and they are all good.
Also, the 02 sensor reading is not right and when I open the throttle the engine pops and bangs. It runs ok at idle and 3000 rpms
I must be missing something somewhere.
Any help?
Thanks
Last edited by Dyno Don; Mar 14, 2017 at 04:13 PM. Reason: correction
Joined: Dec 2004
Posts: 16,734
Likes: 993
From: Mile High Country !!!
Car: 1967 Camaro, 91 z28
Engine: Lb9
Transmission: M20
Axle/Gears: J65 pbr on stock posi 10bolt
Re: Speed density wiring issue
For the fan issue is the programming set to no or nc ?
sounds like you have a bad ecm.
sounds like you have a bad ecm.
Thread Starter
Joined: Mar 2000
Posts: 5,703
Likes: 132
From: Orange, CA
Car: '90 Trans Am-12.45@110.71
Engine: 355 w/AFR 195's Elem. 400/430 HP/TQ
Transmission: Tremec T-56
Axle/Gears: 12 Bolt 3.73
Re: Speed density wiring issue
Normally open
I have tried several known good ecm's, no change
I have tried several known good ecm's, no change
Thread Starter
Joined: Mar 2000
Posts: 5,703
Likes: 132
From: Orange, CA
Car: '90 Trans Am-12.45@110.71
Engine: 355 w/AFR 195's Elem. 400/430 HP/TQ
Transmission: Tremec T-56
Axle/Gears: 12 Bolt 3.73
Re: Speed density wiring issue (solved)
Yes, it was good. (E 15)
N.O. fan fixed that fan issue
The pickup coil in the dizzy was bad
N.O. fan fixed that fan issue
The pickup coil in the dizzy was bad