1990 bought not running still no start
Thread Starter
2nd Gear
Joined: May 2017
Posts: 2
Likes: 0
1990 bought not running still no start
Hi everyone new to the forum. Me and my dad bought a 1990 with blown head gaskets. We towed it home and tried to get it running, but wouldn't start. Just crank. Upon replacing the head gaskets we discovered that the block was cracked so ended up yanking the motor and replacing it with a motor from a 1987 vette. Still no start. We deleted the vats with a vats deleted prom, still no start. It has spark and the timing is set correctly. The fuel pump hums, and the injectors are working via noid light. We undid the fuel rail to confirm it has fuel pressure and it does. The engine has plenty of compression too. It will run with starting fluid but otherwise nothing. Any help is hugely appreciated. Thank you all!
Race Director
Joined: Aug 2000
Posts: 11,470
Likes: 765
if you don't have a factory service manual (FSM) get one.
the first thing I would do is run an actual fuel pressure test. since you said it fires up on starting fluid, I'd look at the fuel system. first thing, check the fuel pressure. sounds like you can hear your fuel pump kick on when you turn the key on, so install a fuel pressure gauge on the Schrader valve - key on, you should get approximately 42psi for a couple seconds, then the pump will kick off - pressure should drop to around 37psi and hold for some period of time. also. pull the vacuum line from the fuel pressure regulator - any gas or indication of leakage?
having an unknown fuel pressure at the rails doesn't mean squat in trouble-shooting tuned ports -- you can have 10psi, and that thing will squirt all day long, and you're going nowhere. pressures are critical. while your at it, if unknown status or no service history, replace the fuel filter. take note and establish a maintenance baseline. good luck - keep us posted. BTW, welcome to the forum.
the first thing I would do is run an actual fuel pressure test. since you said it fires up on starting fluid, I'd look at the fuel system. first thing, check the fuel pressure. sounds like you can hear your fuel pump kick on when you turn the key on, so install a fuel pressure gauge on the Schrader valve - key on, you should get approximately 42psi for a couple seconds, then the pump will kick off - pressure should drop to around 37psi and hold for some period of time. also. pull the vacuum line from the fuel pressure regulator - any gas or indication of leakage?
having an unknown fuel pressure at the rails doesn't mean squat in trouble-shooting tuned ports -- you can have 10psi, and that thing will squirt all day long, and you're going nowhere. pressures are critical. while your at it, if unknown status or no service history, replace the fuel filter. take note and establish a maintenance baseline. good luck - keep us posted. BTW, welcome to the forum.
Last edited by Joe C; May 26, 2017 at 05:58 AM.
Le Mans Master
Joined: Feb 2005
Posts: 6,486
Likes: 566
From: Clearwater Florida
..... Replace or rebuild the fuel injectors ... just because there is fuel pressure in the rail does not mean that its getting delivered at the appropriate amounts to each cylinder .....
Last edited by C409; May 26, 2017 at 07:48 AM.
Melting Slicks
Joined: Sep 2008
Posts: 2,376
Likes: 111
From: Cherokee National Forest TN
Fuel pressure as above.
90 injectors are problematic due to the current corn gas. Injection is batch fire if 1 injector is not functioning properly it will effect the operation of the others.
Ohm test each injector you need 14 to 16 ohms. If any are out of spec leave it/them unplugged.
Try to start the engine it should run on the remaining cylinders = it needs injectors
Good luck
90 injectors are problematic due to the current corn gas. Injection is batch fire if 1 injector is not functioning properly it will effect the operation of the others.
Ohm test each injector you need 14 to 16 ohms. If any are out of spec leave it/them unplugged.
Try to start the engine it should run on the remaining cylinders = it needs injectors
Good luck
Oil Producer
Joined: Apr 2014
Posts: 9,387
Likes: 2,749
what do your spark plugs look like?
you can buy refurbed fuel injectors very cheap if you are in the usa from john bannerman at fuel injector connection. 99% of people on this board appear to use him with 100% satisfaction.
noid light confirms injectors are being told to fire by the ecm. that is all. id check ohm resistance on injectors. they could be shorted open. they could be gummed up and no fuel getting out.
but first id check fuel pressure. observe pressures and bleed off times.
you can buy refurbed fuel injectors very cheap if you are in the usa from john bannerman at fuel injector connection. 99% of people on this board appear to use him with 100% satisfaction.
noid light confirms injectors are being told to fire by the ecm. that is all. id check ohm resistance on injectors. they could be shorted open. they could be gummed up and no fuel getting out.
but first id check fuel pressure. observe pressures and bleed off times.
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