Truck wont start - help needed
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Truck wont start - help needed
First off, the truck has been running awesome until this morning when I went to fire it up...it will not start. It is getting fuel so I have ruled out a fuel issue. I unhooked the main coil wire that goes to the dist. and put a plug on the end of it and had someone crank on it and it has lots of spark there. I also put a test light on the "tach test" and ground and had someone crank and the light blinks rapidly. What/where should I turn next? Is it possible the module went bad? If so, how do you test the module? My apologies if this has been discussed before, I tried searching but couldn't find it and I have stuff to do today which will require this truck to run.
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From: Nuevo Laredo/Laredo Tx.
I've had a similar problem in the past but in my case three things were the problem, Ignition module, pickup coil (it's inside the distrib. cap) and the ignition coil, so I'm pretty sure one of this 3 things is the problem in your truck, good luck!!
Post Fiend
Joined: Sep 2006
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From: Island Southeast Alaska
You didn't say if you had spark at the plugs. If you got spark at the coil wire but not at the plug wire I would suspect something in the distributor. Like the pick up coil. the rotor or cap. Or a bearing in the dizzy. Is there any play in the shaft the rotor cap is on?
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I do have spark at the plugs. Dizzy shaft doesn't have any slop to it. If the the coil is putting spark out, does that mean that the module is fine? I just now finally got it to start. It took a lot of cranking and you can tell by the sound when you give it throttle that something definitely isnt working right. It is running but badly and I don't think I want to try to drive it this way mainly because I think it just might quit working (again). Plugs, cap & rotor are all new.
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From: Moore, OK
I just dealt with similar issues. So lets review what we have (most likely) ruled out:
- fuel delivery
- Spark at the coil
- Spark at the coil rules out pickup coil.
- It cranks fine, so now starter solenoid
Here are some other things to consider:
- Spark at the coil usually rules out ignition module, but they are funny things sometimes
- Have you check for spark at the plugs? Bad wires, dizzy cap or rotor?
- Did you check battery voltage? A weak battery could cause it to crank and not fire.
- Ignition switch maybe? I know it can cause problems, but Im not sure of the symptoms.
- fuel delivery
- Spark at the coil
- Spark at the coil rules out pickup coil.
- It cranks fine, so now starter solenoid
Here are some other things to consider:
- Spark at the coil usually rules out ignition module, but they are funny things sometimes
- Have you check for spark at the plugs? Bad wires, dizzy cap or rotor?
- Did you check battery voltage? A weak battery could cause it to crank and not fire.
- Ignition switch maybe? I know it can cause problems, but Im not sure of the symptoms.
Post Fiend
Joined: Sep 2006
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From: Island Southeast Alaska
I think the ignition is fine. I also think it has jumped timing. And a timing gear set is in order. Loosen the Dizzy and rotate it a little when running. If ya can make it run better doing that than look into a timing set.
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From: Moore, OK
Lots of posts before I posted mine, but look into what arctic is saying. Also, it could be as simple as a choke problem. Make sure it is operating correctly. I have had chokes cause a hard start, rough run situation.
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I will go and see if advancing/retarding the timing has any effect here in a sec. For fun, I checked to see what my fuel pressure was at. Before when I checked around a month or so ago...I think it was at 7 psi. Now when I test it, it is pegging my gauge to the 10 and my gauge doesnt go any higher. The specs on the pump says they put out between 6.5 and 8. What causes the pump to pump such high fuel pressure? Or have I just found an additional problem?
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From: Moore, OK
flooding can definately lead to hard starting and rough running. I couldnt tell you on what would cause high pressure like that, but I can tell you that is way too much. Even 7 is on the high side. Stock specs in my manual say 4-6 psi.
I just changed my fuel pump, but mine was leaking gas into the crankcase.
I just changed my fuel pump, but mine was leaking gas into the crankcase.
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The pump is mechanical. Is this what these pumps do when they begin to go bad? Put out too much pressure? I would think they would do the opposite. I know my edelbrock manual says not to use more than like 6.5 psi. I think I am going to go buy a new fuel pump for it.
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From: Moore, OK
They can do several things when they go bad. Dont know that I have seen one increase pressure, but I have seen them decrease, leak into the engine, leak outside the engine and leak back to the fuel tank. I would say its feasible for pressure to spike if it is bad, but Im no expert on the internal workings.
I would check pressure again to be sure.
A fuel pump is around $25, so it isnt too bad. They arent too hard to swap. One suggestion; make it easier on yourself and unbolt/move the power steering pump if it is in the way. I cut that corner and regretted it trying to install the new one. If you dont have the right tools it may be near impossible without moving it. Even if you can just shift it a little out of the way it will help. Just dont bind up the lines to the pump.
I would check pressure again to be sure.
A fuel pump is around $25, so it isnt too bad. They arent too hard to swap. One suggestion; make it easier on yourself and unbolt/move the power steering pump if it is in the way. I cut that corner and regretted it trying to install the new one. If you dont have the right tools it may be near impossible without moving it. Even if you can just shift it a little out of the way it will help. Just dont bind up the lines to the pump.
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I was reading in my book that the fuel pump when going out can do both, increase pressure or decrease. I remember reading this so if you have a fuel pump that has been on the truck for a long time or you never have touched it then you might check that out. easy and cheap fix.
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I am getting a ride here shortly (dont trust the truck) to the auto parts store to buy a fuel pump. For $26.00 its not bad. Thats weird they can actually increase pressure when they go bad. Guess you learn something new every day!
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From: Moore, OK
I hope thats the problem. I have never seen one increase, but I dont know what else would cause such high pressures. Good luck. Its a little messy. Have some kind of plug ready for the gas line and dont spill any on your face.
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