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S4 not starting at all....
Pelicans....
I could use some insight here. After replacing my 89 motor with another S4 motor, the car will not start at all. I crank it over and over again, and it wont even attempt to fire. Also replaced the battery, the knock sensors, crank position, and a plethora or other stuff while the motor was out. I have updated CPUs in the EZK and LH, and have shark tuned with basic settings to get it started. Here is the profile: Rotrex supercharger @ 6lbs. 36LB injectors some facts: the engine is getting fuel the engine has spark (at both distributors). NOID lights show that injectors are working (correct pulse) Engine has compression Original motor started and RAN with the same injectors, and SAME EZK and LH Eproms (no supercharger connected at that time). I've verified that connectors on positive terminal are snug There are two clicks when turning on the ignition (not continuous clicks, which indicates a bad LH) Reground cams to original factory specs Replaced ignition, and fuel pump relays. Removed the fuel pump relay - Jumped the 30 and 87 contacts, and fuel pump ran constantly as expected, but car still did not start. Other than replacing the motor, no other changes have been made. Any insight would be appreciated. Last edited by Yellowb1rd; 06-03-2014 at 07:51 PM.. |
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#1-Is your harmonic balancer on backwards? Can you read the numbers on the harmonic balancer from the front of the engine? If it's on backwards, you can have fuel, compression, and spark, but the engine won't start because it'll all be happening at the wrong time for correct engine operation.
#2- Do the LH and EZF for the '89 have the same pin output as previous year computers? I know previous year computers can't be used in 89 and up because the older computers don't have the digital dash drivers. Maybe there are other changes that prevent correct engine operation.
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John Curry (Drift King) 928OC member Grand Prix White 1994 GTS AT (The GTS) Black 1989 GT (The GT) and Cobalt Blue 1989 S4 AT (The Blue Car) 1986 Euro AT Indishrot 1984 Euro S AT (The Stepson) and Black Metallic 1984 Euro S 5 speed (The Schwartz) |
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"Other than replacing the motor, no other changes have been made."
Well this is a big "other". Did you do the motor work? Are cams back in correctly? So many variables to try and trace down. I would start with making sure the motor was put back together correctly and cams, timing gears have been checked for proper alignment with crank timing marks.
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1986 928S 32 valve engine All stock, automatic, 539 Weissgold Metallic, 70K original miles, Hankook Ventus 2 tires. Previously owned: 67 Vette, 427 L88 Stingray, 74 De Tomaso Pantera L. Latest addition: 2000 BMW Z3 Roadster |
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Fuel, spark, compression.
Do a compression test, same time I would attempt a start just prior to it (and pulling the fuel pump relay for the compression test) and check plugs for fuel. Check the ignition timing. Put the factory chips back in for now. Any gas smell at exhaust? Check fuel pressure. Listen for injector click.
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In post #1, you state that the engine has fuel, spark at both distributors and compression.
Timing of at least one of those events has got to be incorrect, or the engine would run
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John Curry (Drift King) 928OC member Grand Prix White 1994 GTS AT (The GTS) Black 1989 GT (The GT) and Cobalt Blue 1989 S4 AT (The Blue Car) 1986 Euro AT Indishrot 1984 Euro S AT (The Stepson) and Black Metallic 1984 Euro S 5 speed (The Schwartz) |
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Quote:
The car is an '89 btw with 89 EZK, and LH. |
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Quote:
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A Wrench
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Failed LH.
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Petie3rd
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^^^^ lets put it another way,
any clicking of the injectors before the engine has begun to crank over, indicates computer failure
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^^^ Stan ^^^ 2019 BMW K1250 GS 2016 HD RK 1988 S4 Auto , Elfenbein Perlglanz, Pearl Gray 1982 5sp Met black and tan sport seats |
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I certainly appreciate the feedback, but interestingly enough, when I jump the fuel pump relay where it is constantly running, it still doesn't start. The LH is essentially bypassed at that point. That makes me doubt a faulty LH.
Last edited by Yellowb1rd; 06-05-2014 at 08:11 PM.. |
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Fuel pump running doesn't make the injectors open, only the brains do that.
When Sean says its X, generally its X. When Stan says its X, generally its X. When Sean and Stan both say its X, its X. |
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Petie3rd
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Thomas ....the solution, take your computers and put them in a good running car/engine, see if the other car will run
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BTW, the clicking turned out to be the fuel pump relay. Completely normal. It's just a lot louder with the panel off.
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Quote:
ALSO, the clicking turned out to be the relays, which is completely normal. Go out and turn your ignition on and you'll hear those clicks too. It's just a lot louder sound when the fuse panel and carpet are out of the way. I realized this because I tested the relays using my own power source, and BEHOLD, same sound! I'm also presuming that the continuous clicking that indicates a bad LH would be caused by sending incorrect signal via the relay, hence opening and closing continuously. Remember, when starting an autobox 928, the fuel pump initially does not run continuously. Let's not have pissing matches here by saying things like me right + him right = We're right. Let's try to figure out the issue together, because that's what these forums are for. I'll find the issue myself eventually, but I'm trying to facilitate the process, which I'll share on the forum for all to benefit from. The bad LH road we're going down here is not the right one. If I'm wrong, I'll be the first to broadcast it, but if faulty LH, 'no flashy' on the Noid light. Since the injectors blink (as shown by the Noid light- blinking indicates a proper signal), the LH is probably just fine, else what is the purpose of the Noid light diagnostics? The incorrect ignition timing seems more likely than a bad LH. It's definitely firing. It's definitely getting fuel to the cylinders. But is it firing at the CORRECT time? Last edited by Yellowb1rd; 06-06-2014 at 08:08 PM.. |
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Petie3rd
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Thanks for the update.
BTW I am providing you my best guess, given the information you are providing. Relays clicking when the key is turned, is completely different than the fuel injectors clicking when the key is turned. I would still like you to install your computers into a good running car , they dont have to be bolted down. the timing is set by the computer so its not something that you can adjust, the firing order can be changed by mis routing the plug wires, and or the timing marks could also be off, usually its a damper thats installed the wrong way
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^^^ Stan ^^^ 2019 BMW K1250 GS 2016 HD RK 1988 S4 Auto , Elfenbein Perlglanz, Pearl Gray 1982 5sp Met black and tan sport seats |
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timing belt
I think the thing to do here is to check the tension of the timing belt, if tension is loose it is possible the belt has jumped a cog or two and the engine is now out of cam timing. I know it is a lot of work but at this point if everything else is coorect(i.e. ignition, spark and compression) Only timing is left for propre engine function.
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timing
If the engine was recently assembled and has run since then, it is possible retensioning will be necessary(as the dealer would require a scheduled retensioning after something like 1500 miles) If this is the case my thoughts on the timing belt jumping cogs would be likely. The timing belt light should come on possibly if tension is loose..but it is also easy to incorrectly reassemble the tensioner warning system wiring... You stated that the engine has compression so i am assuming there are no bent valves..
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Have you simply pulled plugs to see if its getting fuel. If you've got fuel, spark and compression then Harborman's advice would be the first step (i know you already know this) Get the basics covered first. You'll get it running Yellowbird ![]()
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Yellowbird, The cylinders are numbered front to back 1-4 on right side of car front to back 5-8 on the left side of the car. Where the plug wires put on in that order?
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John Curry (Drift King) 928OC member Grand Prix White 1994 GTS AT (The GTS) Black 1989 GT (The GT) and Cobalt Blue 1989 S4 AT (The Blue Car) 1986 Euro AT Indishrot 1984 Euro S AT (The Stepson) and Black Metallic 1984 Euro S 5 speed (The Schwartz) |
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