86na hard to start
09-15-01, 12:20 AM
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86na hard to start
This is a friends car that I'm fixing. When the car is cold, you have to crank and crank the engine, After probably the third or fourth long crank it shows some signs of life. It will slowly start, first a few pops, then it gets faster and faster until it actually starts. While its 'starting' you have to keep the starter engaged or it will die.
The car has a rebuilt engine (no compression probs), primary injectors don't leak, lots of fuel preasure. The BAC valve is blocked off, but the AWS solenoid is hooked to a switch so that once the engine starts it holds at 2k rpm.
Timing is bang on, tps is set, idle speed is set at about 850 to compensate for no BAC. All the vaccuum lines have been replaced and it has a new fuel filter.
There is a smell of fuel after cranking the engine for a while, I don't think that it is a flooding problem though, if I pull the EGI fuse and do the unflooding procedure it does nothing, there also used to be a fuel cutoff switch(now used for AWS) but I took it ouf because it didn't help at all.
There is spark at all the plugs. I did notice though that it was't a very blue spark.
Once it does start it takes a while before it runs on its own, it seems to have a bit of a miss at idle.
Also, could a "too free flowing" exhaust not have enough back preasure for the engine to start? It seems that it spins quicker (engine kinda firing) with the clutch up. If you push it down the cranking speed decreases, so this makes me think the added resistance is helping it start. The car has a header, blown out mufflers and an exhaust leak. (Soon to be replaced)
Sorry for making this post so long but I wanted to try to give as much detail as possible.
The car has a rebuilt engine (no compression probs), primary injectors don't leak, lots of fuel preasure. The BAC valve is blocked off, but the AWS solenoid is hooked to a switch so that once the engine starts it holds at 2k rpm.
Timing is bang on, tps is set, idle speed is set at about 850 to compensate for no BAC. All the vaccuum lines have been replaced and it has a new fuel filter.
There is a smell of fuel after cranking the engine for a while, I don't think that it is a flooding problem though, if I pull the EGI fuse and do the unflooding procedure it does nothing, there also used to be a fuel cutoff switch(now used for AWS) but I took it ouf because it didn't help at all.
There is spark at all the plugs. I did notice though that it was't a very blue spark.
Once it does start it takes a while before it runs on its own, it seems to have a bit of a miss at idle.
Also, could a "too free flowing" exhaust not have enough back preasure for the engine to start? It seems that it spins quicker (engine kinda firing) with the clutch up. If you push it down the cranking speed decreases, so this makes me think the added resistance is helping it start. The car has a header, blown out mufflers and an exhaust leak. (Soon to be replaced)
Sorry for making this post so long but I wanted to try to give as much detail as possible.
Last edited by Brian P; 09-15-01 at 12:22 AM.
09-16-01, 01:38 AM
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I would be suspicious of a weak spark. If you are getting air and fuel, then spark is the only thing left. Especially the primary coil. Low backpressure should be no problem, there are many people who run freeflowing exhauts without any problems.
09-16-01, 09:23 AM
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I think your right, spark is my next checks... Strange though, if you roll start it it goes fine, same if you give it a shot of ether.
One thing I did notice (havn't confirmed yet) is that L1 and L2 should spark at the same time correct? so it should matter which wire I put the timing light on right? The thing is that I noticed that if I put it on L2 instead of L1 it doesn't even come close to hitting the timing mark. I'm gping to go confirm that and then try my t2 to see if its the same.
One thing I did notice (havn't confirmed yet) is that L1 and L2 should spark at the same time correct? so it should matter which wire I put the timing light on right? The thing is that I noticed that if I put it on L2 instead of L1 it doesn't even come close to hitting the timing mark. I'm gping to go confirm that and then try my t2 to see if its the same.
10-05-01, 12:36 AM
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I actually had the exact same symptoms you did not too long ago on my 86 Rex. I eventually found out it was a defective battery.
You might want to check that, if you haven't. I'd try to crank it and you could hardly hear it turn very very slowly, then the turning would gradually come faster and faster and then it would finally start. After driving for a bit it would start right back up because the battery would have a little charge in it, but the battery wouldn't hold the charge for long. anyhow hopefully your prob;em is as simple as this.
You might want to check that, if you haven't. I'd try to crank it and you could hardly hear it turn very very slowly, then the turning would gradually come faster and faster and then it would finally start. After driving for a bit it would start right back up because the battery would have a little charge in it, but the battery wouldn't hold the charge for long. anyhow hopefully your prob;em is as simple as this.
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