no start
Thread Starter
6th Gear
Joined: Apr 2019
Posts: 6
Likes: 0
no start
89 cranks and trys to start. seems like one set of injectors isn't firing. fuel pressure is good 43. spark is good, ecm has no set codes. VATS is NOT disabled but seems to be working. service engine soon light and battery symbol are lit when key is in the on position. don't know where injector relays are to check or if there are any. have not scrutinized the wiring diagrams. this is my first vette. had an 89 IROC no issues. any guidance will be appreciated.
Thread Starter
6th Gear
Joined: Apr 2019
Posts: 6
Likes: 0
Both fuses check ok. Checked an injector connector on each bank left and right with a NOID light. Im going to do a complete check of all and check the injector coils at the same time. Then I guess pull the plugs and have a look there also unless you can suggest something on the injector aspect.
Le Mans Master
Joined: Sep 2013
Posts: 6,192
Likes: 750
From: near the thumb in the mitten
Spark fuel pressure injector pulse leaves timing and compression. You could verify firing order, rotor points at 1 or 6 with timing mark at tdc on tab. Make sure balancer ring hasn't slipped. Any repair prior to no start?
Thread Starter
6th Gear
Joined: Apr 2019
Posts: 6
Likes: 0
heads off top end work done but car ran fine for a period. began to overheat and was parked by previous owner. he checked coolant etc ran fine in garage for 20 min or so and he lost interest for about a year. went to start and couldn't. I bought his headache. compression sounds good and very equal in all eight. I'm not new to cars but I'll ask the stupid question regardless...old fuel smells but wouldn't cause this much of a problem or am I mistaken?
Thread Starter
6th Gear
Joined: Apr 2019
Posts: 6
Likes: 0
Not a fan myself but already went down that path. while It shouldn't matter which injector connector on even or odd bank connects to which injector the connectors on back end of the engine were crossed coming out of the conduit so I switched them. Still acting the same pretty much but desperate and feathering/pumping the throttle got it to run for about five seconds sounding like it firing on two cylinders. I was able to confirm this as the exhaust manifold on #2 and #5 were warm. going back to the injector electrical check tomorrow, verify every connector with noid light and ohm the coils. then Im going to pull the dist cap plugs etc. fuel timing compression and spark. I hope the deep mechanics are intact. I don't think It would sound so even in compression cranking if the cam snapped somewhere. rotor will tell. Thank you very much for the input. Ill let you know what I come up with next.
Pro
Joined: Dec 2018
Posts: 728
Likes: 420
From: Wisconsin
2023 Corvette of the Year Finalist - Modified
2022 C4 of the Year Winner - Modified
Finalist 2020 C4 of the Year - Modified
Are you sure that the rotor is pointing at "1" on TDC of the compression stroke? I ask because I had a senior moment installing the distributor in the Vortec in my Suburban. (Felt like a complete idiot once I realized my mistake. Not one of my finest moments...) I had similar symptoms to you. Had compression, spark, fuel, but just wouldn't completely fire. Had to put the motor back at TDC for cylinder 1 and re stab the distributor. Fired up instantly once I fixed my mistake.
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Melting Slicks
Joined: Nov 2007
Posts: 2,830
Likes: 147
From: Gainesville FL
It will be interesting to see what the plugs look like. Double no triple-check that the plug wires are properly connected to the correct cylinders. Also a bad coil will also cause a similar situation with no codes.
Drifting
Joined: Feb 2016
Posts: 1,384
Likes: 339
From: Simi Valley CA
A common no start problem with these is the icm. Its about 20.00 for the part and goes right under the rotor in the distributor. Pretty cheap easy job. The connector almost always breaks and is too brittle to reuse.
Thread Starter
6th Gear
Joined: Apr 2019
Posts: 6
Likes: 0
Its like the man said, compression spark timing and fuel. I've read and heard so much about the VATS and everything else about these things and it will put a brick in your head. stick to the basics and don't let the horror stories sway your common sense. Compression, got it, spark, got it, timing got it, fuel got it and correct pressure, power to the injectors, got it, injector pulse, cant check it don't have a scope so lets look at it like this. Key on pressure to 42, alligator clips from the battery to the injector (yes, polarity is important), click and pressure goes down, key on again 2 seconds pressure up 42, next injector, same deal until all have been verified and have flow. Crank it and Vroom! took awhile to smooth out and fire evenly but problem solved. Exhaust smells awful (old gas) so you cant trust peoples perception of how long something has sat in the garage. sticky breaks and a couple simple fixes and I'm gonnadrive89!!! Thanks to all for the input. It helps to keep stay focused.