1985 Fuel Pressure
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Instructor
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1985 Fuel Pressure
What is the proper fuel pressure for a 85? Some sources seem to claim it should be lower than the 86-87 cars, but others claim it is the same.
I get 36 with vacuum on and 42 with vacuum off, which seems to match for the later cars. But other sources say the 85 should be 30-34 idle and 39 vacuum off, does anyone know for sure? FSM gives a vague range. It looks like someone changed my regulator so my best guess is someone put a later one on.
Car seems to run fine other than poor fuel economy, but just want to make sure what the pressure should be.
I get 36 with vacuum on and 42 with vacuum off, which seems to match for the later cars. But other sources say the 85 should be 30-34 idle and 39 vacuum off, does anyone know for sure? FSM gives a vague range. It looks like someone changed my regulator so my best guess is someone put a later one on.
Car seems to run fine other than poor fuel economy, but just want to make sure what the pressure should be.
Last edited by jdjenk; Dec 24, 2021 at 11:51 AM.
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35 idle
if u have poor fuel economy u could have a vac leak affecting bank 1, or you could have injectors that are leaky and dumping extra fuel.
85’s are tricky to scan real time because they only communicate in field service mode which alters thier behavior while scanning it.
have you got a high idle?
if u have poor fuel economy u could have a vac leak affecting bank 1, or you could have injectors that are leaky and dumping extra fuel.
85’s are tricky to scan real time because they only communicate in field service mode which alters thier behavior while scanning it.
have you got a high idle?
Thread Starter
Instructor
Joined: Jan 2021
Posts: 146
Likes: 37
35 idle
if u have poor fuel economy u could have a vac leak affecting bank 1, or you could have injectors that are leaky and dumping extra fuel.
85’s are tricky to scan real time because they only communicate in field service mode which alters thier behavior while scanning it.
have you got a high idle?
if u have poor fuel economy u could have a vac leak affecting bank 1, or you could have injectors that are leaky and dumping extra fuel.
85’s are tricky to scan real time because they only communicate in field service mode which alters thier behavior while scanning it.
have you got a high idle?
Someone had certainly messed with this car - it had a JET chip in it and the maf had the cover removed and messed with somehow. I swapped the chip for the stock one and the maf for a new one and it helped. Doesn't seem any slower either.
Last edited by jdjenk; Dec 24, 2021 at 02:30 PM.
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From: Rockland County, New York
Thread Starter
Instructor
Joined: Jan 2021
Posts: 146
Likes: 37
So I did some more messing around and turns out I DID have a giant vacuum leak on the drivers side. The hose from the metal bit that the PCV valve and vacuum reservoir connect to was too big and not clamped, so I got some smaller hose and managed to get a clamp on one side at least. It still leaks a little but it certainly leaks a hell of a lot less now. We'll see if it improves the fuel economy any, the throttle response and cold idle are definitely a lot better.
