Help going on holiday
Thread Starter
Racer
Joined: Aug 2000
Posts: 339
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From: cambridge UK Cambs
Help going on holiday
I have started having problems starting on my 86 Auto
when the car starts it will not rev and runs on very rough.
looking at the fuel pressure it is about 10 and then sudenly climbs to 40 and the engine clears and runs fine..
Does the pump run from a staight feed from the ignition or does it have any controls from the vats or anything?
Thanks for the help
Barry
when the car starts it will not rev and runs on very rough.
looking at the fuel pressure it is about 10 and then sudenly climbs to 40 and the engine clears and runs fine..
Does the pump run from a staight feed from the ignition or does it have any controls from the vats or anything?
Thanks for the help
Barry
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
After startup the fuel pump is powered by the oil pressure switch.
It sounds like the fuel pump is going out. You might change the filter to see if that fixes the problem.
In case you need to change the pump and filer sock, it's only an hour or so job.
It sounds like the fuel pump is going out. You might change the filter to see if that fixes the problem.
In case you need to change the pump and filer sock, it's only an hour or so job.
Thread Starter
Racer
Joined: Aug 2000
Posts: 339
Likes: 0
From: cambridge UK Cambs
65Z01
Thanks for the info.
As far as I can see from my manuals he pump should get a power from the ignition for 2 seconds then only when you get oil pressure above 28 psi or signal from the HEI.
Can any one confirm this and also confirm that the VATS does not interfere?
Strange thing is it only happemns when the ambient temp is high???
and the car has heat soaked for a while
In trouble over this , if I have to take the Citroen to france this week end Lyn will kill me!!!!!
Thanks for the info.
As far as I can see from my manuals he pump should get a power from the ignition for 2 seconds then only when you get oil pressure above 28 psi or signal from the HEI.
Can any one confirm this and also confirm that the VATS does not interfere?
Strange thing is it only happemns when the ambient temp is high???
and the car has heat soaked for a while
In trouble over this , if I have to take the Citroen to france this week end Lyn will kill me!!!!!
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
There is conflicting data on this topic. My '88 GM Shop Manual text body states that the ECM holds the FP relay On when the engine is running but the Electrical Suppliment states in the wiring diagram that the ECM only holds the FP relay on during startup.
Anyway, since the ECM only controls the FP relay, the VATS can only effect FP operation on startup as the power from the fusable link goes to the FP pressure switch and then to the FP Fuse and onto the FP.
The oil pressure switch on the stalk to the left of the dist is the one with the Orn & Red wires. If you jumper that connector the fuel pump should run as the Orn wire is hot all the time. At least this should tell you if the problem is with the oil pressure switch.
If you can jumper a switched source of +12Vdc to the ALDL pin G it will power the pump. Remember that the FP Fuse is 10 Amp so use care in selecting a switched power source.
Anyway, since the ECM only controls the FP relay, the VATS can only effect FP operation on startup as the power from the fusable link goes to the FP pressure switch and then to the FP Fuse and onto the FP.
The oil pressure switch on the stalk to the left of the dist is the one with the Orn & Red wires. If you jumper that connector the fuel pump should run as the Orn wire is hot all the time. At least this should tell you if the problem is with the oil pressure switch.
If you can jumper a switched source of +12Vdc to the ALDL pin G it will power the pump. Remember that the FP Fuse is 10 Amp so use care in selecting a switched power source.
Last edited by 65Z01; Aug 31, 2005 at 03:23 PM.
Thread Starter
Racer
Joined: Aug 2000
Posts: 339
Likes: 0
From: cambridge UK Cambs
Thanks
I will try tomorrow on a cold engine.
From the above are we saying that if i put a bulb between pin G and ground it will act as a test to see when the FP is powered.
Thanks
Barry
I will try tomorrow on a cold engine.
From the above are we saying that if i put a bulb between pin G and ground it will act as a test to see when the FP is powered.
Thanks
Barry
