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Alright, I'm at wits end. I have a 1989 GTA with the 5.7l. I had the fuel pump replaced recently because it died. Within 2-3 weeks of getting it back, I began getting crank but no start problems. This would often correct itself if I just kept futzing with turning the ignition on and off for like 15-20 minutes. Eventually I narrowed down the most likely culprit to the fuel relay...so I replaced it. Things worked great for 2-3 weeks then it went back to crank-no start. This time it left me stranded at work so I had it towed to the shop that did the fuel pump replacement for me. They found the oil pressure sending unit was bad and the plug on...I think they said the secondary fuel pump relay?...had effectively disintegrated. So they replaced both of those items and it worked great....for about 2 weeks. Now I'm back to crank-no start and zero fuel pressure again. I don't even know where to begin looking at this point. So I'm here to look for some advice from people that have more experience than me. Please help before I completely lose what little sanity I have left.
Thanks for the replies. That link helped a good bit. I unplugged the relay and jumped the 12v to the pump. (Also, that's the plug that the shop replaced and the new one has every wire as white...so figuring out which was which was "fun".) The first time I did that I heard a click somewhere under else under the hood but couldn't tell where, but the pump didn't turn on. I only jumped it for about 2 seconds to simulate turning the ignition on. I did that a second time and got the same result. The third time, however, I heard the pump kick in and start priming the fuel rail. I reconnected the plug to the relay and the engine started right up and ran just fine.
Given that it wouldn't kick on being basically hotwired around the relay implies to me that the relay probably isn't the issue. I suppose I need to now get under the back of the car and check the plug by the diff for grime and corrosion. Correct me if I am wrong, but if the plug connection back there is in good shape, the issue may be that my new fuel pump is failing and I need to check the ohms on the pump side of that connector?
Yes, that would certainly be the next easiest component to test and visually inspect, provided you can get your car off the ground sufficiently. I am confused as to why the shop had to replace the wiring to the relay (and used all white wires no less), unless it was completely corroded or melted beyond repair. do you have a picture of what they did in the relay area? (there is no such thing as a secondary relay, just the one relay and the harness/plug going to it) Just trying to visualize possible causes.
The terminals in the plug had corroded badly and had started actually coming apart. So they replaced it. It looks like a full replacement plug and not just like they put new wires and terminals in the old plug casing. I don't have a photo but they did show me the plug when I picked the car up from them. They're a reputable shop and work on a lot of older cars. I'm a shadetree mechanic but I'm far more familiar with carb setups from the 70s and early 80s. And to your point, anything that requires getting the car of the ground more than a foot...I can't manage in my garage.
Just to loop back to this, I got under the car and checked the connector by the tank. It didn't look all that dirty but I cleaned it a bit and sprayed some deoxit on both sides of the plug. it's been working fine since then so I assume it was a poor connection back there. I also did the ohm test on the pump while I had it apart and it tested out fine.
And to take this on a slight tangent...is there supposed to be any kind of plastic or metal shield under the tank? Mine doesn't have anything and I sometimes hear what sounds like bubbling/boiling from the tank after I've been out and about for a while and there's almost always a streak down the quarter panel below the gas door indicating fuel spillage even if I haven't had the cap off since the last wash. The muffler is only like 4-5 inches below the bottom of the tank so I am wondering if the heat from the exhaust is the issue and if there is supposed to be some kind of shielding between those two.
yes from the factory there is a sheet metal "heat shield" between the muffler and tank. You may also want to check or replace your vent valve, this should be blowing off excess pressure long before your gas gap, they are a common failure if they are original/plastic corroded https://www.hawksmotorsports.com/82-...oration-parts/
Well, crud. I don't have that shield/deflector panel and my google-fu is failing me on finding somewhere I can source one. I'll probably go ahead and toss that valve in my next Hawks order. It's not expensive and if they are known to fail, it won't hurt to go ahead and get it.
Any ideas where I could put my hands on one of those shields?
03-15-2024, 11:57 AM
