'86 951 No Start, Fuel Related?
05-23-2010, 06:57 PM
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'86 951 No Start, Fuel Related?
***Thread has been moved to 951 specific forum. Contribute here. Thank you.***
First off, thanks in advance to anyone who can help with this.
My car hasn't run in just under a year. I worked on it a lot last spring, ran it a few times last summer, and in the fall after replacing the cooling fan thermoswitch in the radiator, noticed a fuel leak over the header. It was cold outside by that point, so I let it sit for the winter (no garage). I just installed new LR lines, and the car won't start. When turning the key, it kicks a few times like it wants to start, but won't run.
If I remove the fuel pump sender fuse, the engine runs for about 3 seconds and dies, as one would expect a car with no fuel pump to do. From this, I concluded that spark is good and the problem must be fuel related. I thought the FPR may have failed shut and the engine was getting too much fuel to start and idle. I disconnected the fuel return line from the FPR and ran a new piece of line from the FPR into a container and tried to start the car. Same no-start condition and fuel gushed out, so I figured it can't be getting too much fuel.
Other troubleshooting steps I've taken:
Replaced DME relay with new one
Checked speed & reference sensors w/ multimeter a la Clarks Garage
Bypassed factory alarm a la Clarks Garage
Check plug wire routing, cap & rotor condition: good
Unplugged one fuel injector, tried to start, no appreciable difference
Listened for injectors firing when trying to start: yes, they are ticking
Unplugged AFM, tried to start, no difference
Then I noticed something bad: milkshake in oil. Coolant still looks fine. My first thought was bad headgasket allowing milkshake into the cylinders and preventing the engine from starting, but then why is it able to run (briefly) without the fuel pump? Furthermore, the car is barely modded (boost enhancer, that's it) and I didn't run it hard at all last summer. It ran fine until an electrical problem (thermoswitch) sidelined it. I have trouble believing that it blew the HG just from sitting. I can also see some oil leakage around the oil cooler, so I think it's bad seals there causing the milkshake. I know I need to solve the milkshake problem before driving the car, but I'd like to at least get it running before jumping into another project.
Any ideas? Can anyone explain why the car will run for a few seconds without the fuel pump fuse, but not at all with it? Is it definitely the headgasket and I'm just in denial? Is there a way to prove the HG is bad without taking half the engine apart?
Thanks for reading this far and thanks again to anyone who can shed some light on this.
First off, thanks in advance to anyone who can help with this.
My car hasn't run in just under a year. I worked on it a lot last spring, ran it a few times last summer, and in the fall after replacing the cooling fan thermoswitch in the radiator, noticed a fuel leak over the header. It was cold outside by that point, so I let it sit for the winter (no garage). I just installed new LR lines, and the car won't start. When turning the key, it kicks a few times like it wants to start, but won't run.
If I remove the fuel pump sender fuse, the engine runs for about 3 seconds and dies, as one would expect a car with no fuel pump to do. From this, I concluded that spark is good and the problem must be fuel related. I thought the FPR may have failed shut and the engine was getting too much fuel to start and idle. I disconnected the fuel return line from the FPR and ran a new piece of line from the FPR into a container and tried to start the car. Same no-start condition and fuel gushed out, so I figured it can't be getting too much fuel.
Other troubleshooting steps I've taken:
Replaced DME relay with new one
Checked speed & reference sensors w/ multimeter a la Clarks Garage
Bypassed factory alarm a la Clarks Garage
Check plug wire routing, cap & rotor condition: good
Unplugged one fuel injector, tried to start, no appreciable difference
Listened for injectors firing when trying to start: yes, they are ticking
Unplugged AFM, tried to start, no difference
Then I noticed something bad: milkshake in oil. Coolant still looks fine. My first thought was bad headgasket allowing milkshake into the cylinders and preventing the engine from starting, but then why is it able to run (briefly) without the fuel pump? Furthermore, the car is barely modded (boost enhancer, that's it) and I didn't run it hard at all last summer. It ran fine until an electrical problem (thermoswitch) sidelined it. I have trouble believing that it blew the HG just from sitting. I can also see some oil leakage around the oil cooler, so I think it's bad seals there causing the milkshake. I know I need to solve the milkshake problem before driving the car, but I'd like to at least get it running before jumping into another project.
Any ideas? Can anyone explain why the car will run for a few seconds without the fuel pump fuse, but not at all with it? Is it definitely the headgasket and I'm just in denial? Is there a way to prove the HG is bad without taking half the engine apart?
Thanks for reading this far and thanks again to anyone who can shed some light on this.
Last edited by SkippyCrunchySmooth; 05-24-2010 at 07:37 PM. Reason: moved thread
05-24-2010, 06:27 PM
#2
Burning Brakes
Did the temp warning light ever come on? These are aluminum, open-deck motors. It wouldn't take much to cause failure, especially on an 86 951, a year with weaker head studs (improved 87+).
That said, it sounds like a fuel issue. Did you make a jumper for the DME relay? Your car sounds just like one of my 951s that had a failed fuel pump. Make a DME jumper (I believe Clark's has this, or you could just look at the relay diagram)...if that doesn't work, pull the pump and bench test it (don't run it for more than a second or so though, as it needs fuel for cooling and load). It should torque over like a banshee. The pump is external and easy to remove.
That said, it sounds like a fuel issue. Did you make a jumper for the DME relay? Your car sounds just like one of my 951s that had a failed fuel pump. Make a DME jumper (I believe Clark's has this, or you could just look at the relay diagram)...if that doesn't work, pull the pump and bench test it (don't run it for more than a second or so though, as it needs fuel for cooling and load). It should torque over like a banshee. The pump is external and easy to remove.