3.0 Engine no start
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Freshman User
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From: Greenville, In.
3.0 Engine no start
I have a '94 Ranger. 40K miles. Over the last year or so, the check engine light will come on while driving. It goes back off in a random manner. The engine never has seemed to run well. It always did have a long crank time to start, I.E., it never fires instantly like most modern engines. Surges, low power. Lately, it takes spells of not starting. Turns over fine but won't hit. It seems to happen several hours after the last drive. After some heat soak. Let it set for several more hours and it starts. I know the coil isn't firing when it doesn't start as verified by pulling the coil wire and routing to a ground.
Cargo Master
Joined: May 2001
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Like the man said either a bad Ignition control module or a bad coil or a bad pickup coil in the distributor.I think the 94 3.0 still had distrbutors you can check the coil with an OHm Meter and you can see if the icm is suppling the pulse to the coil via a test light. I have seen all three components have heat soak related problems. If it is a distributor model them also check for a bad cap or rotor.
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Freshman User
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From: Greenville, In.
I've never changed the plugs or wires. Wouldn't think I'd have to with 40K on it. It doesn't misfire that you can feel. Yes, it has a distributor.
A couple of questions based on these two responses:
Which wire do I probe from the ICM to get a tach signal?
Would any of these items listed cause the check engine light to come on and then go off while driving?
Thanks.
A couple of questions based on these two responses:
Which wire do I probe from the ICM to get a tach signal?
Would any of these items listed cause the check engine light to come on and then go off while driving?
Thanks.
Cargo Master
Joined: May 2001
Posts: 3,208
Likes: 13
Yes it can cause a cel to come on.the computer is controlling the timing and in this engine it is actually controlling the coil on off pulses . I am not sure how to check the coil pulses on this set up the tan/yellow wire comes from the coil to the icm and then the pcm tells this icm to turn ground on and off through the icm so I would probably check that wire.
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Freshman User
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From: Greenville, In.
Originally Posted by wtroger
Yes it can cause a cel to come on.the computer is controlling the timing and in this engine it is actually controlling the coil on off pulses . I am not sure how to check the coil pulses on this set up the tan/yellow wire comes from the coil to the icm and then the pcm tells this icm to turn ground on and off through the icm so I would probably check that wire.
Cargo Master
Joined: Apr 2003
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From: Frequently frozen MN
Have you tried to see if there are any codes set? It's pretty easy to do -- 94s may even let use the CEL to read the codes -- earlier ones made you use a separate light or meter. You can probably find the procedure in a Haynes or Chilton's -- it may even be here at FTE.
Having said that, you can pull apart the one wire connector and see if you get a spark then. There are a few variations in style, but they all serve to disconnect the ICM from the computer to set base timing. If you don't have
any spark when you disconnect the connector, it's
1. ICM
2. DIS trigger
3. Coil -- or power to the coil.
As for plugs, I had a 91 3.0, and it still ran when the electrodes were flat ( that's how they were when I bought it. )
ford2go
Having said that, you can pull apart the one wire connector and see if you get a spark then. There are a few variations in style, but they all serve to disconnect the ICM from the computer to set base timing. If you don't have
any spark when you disconnect the connector, it's
1. ICM
2. DIS trigger
3. Coil -- or power to the coil.
As for plugs, I had a 91 3.0, and it still ran when the electrodes were flat ( that's how they were when I bought it. )
ford2go
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Freshman User
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From: Greenville, In.
Originally Posted by ford2go
Have you tried to see if there are any codes set? It's pretty easy to do -- 94s may even let use the CEL to read the codes -- earlier ones made you use a separate light or meter. You can probably find the procedure in a Haynes or Chilton's -- it may even be here at FTE.
Having said that, you can pull apart the one wire connector and see if you get a spark then. There are a few variations in style, but they all serve to disconnect the ICM from the computer to set base timing. If you don't have
any spark when you disconnect the connector, it's
1. ICM
2. DIS trigger
3. Coil -- or power to the coil.
As for plugs, I had a 91 3.0, and it still ran when the electrodes were flat ( that's how they were when I bought it. )
ford2go
Having said that, you can pull apart the one wire connector and see if you get a spark then. There are a few variations in style, but they all serve to disconnect the ICM from the computer to set base timing. If you don't have
any spark when you disconnect the connector, it's
1. ICM
2. DIS trigger
3. Coil -- or power to the coil.
As for plugs, I had a 91 3.0, and it still ran when the electrodes were flat ( that's how they were when I bought it. )
ford2go
I have a scanner. I just don't remember how to use it on an EEC III system. Been too many years. I bought a Haynes a year or so ago. the procedure wasn't in that.
I haven't driven the truck since I made the first post here. I believe from what you guys have posted, the problem is in the ICM. I believe this engine has a TFI module on th distributor. The one wire deal to disconnect it sounds familiar. I'll have to look but best I remember, if the FTI goes bad, it won't run. Still, I think that's where the trouble is as sometimes while driving, it gives every indication the timing isn't being controlled. Either too fast or too slow. It even spark knocks sometimes.
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From: Liberty, MO
Originally Posted by Mike McKown
I've never changed the plugs or wires. Wouldn't think I'd have to with 40K on it. It doesn't misfire that you can feel. Yes, it has a distributor.
Which wire do I probe from the ICM to get a tach signal?
Which wire do I probe from the ICM to get a tach signal?
The signal for the tach comes from the negative side of the ignition coil. Its a tan/brown wire that runs from there, across the engine and up to the drivers side of the radiator, then straight through the firewall and into cab.
Also whether or not it has 40K on the ticker, its a 13 year old truck, its time for new wires no matter how you look at it. There's no way that the wires arent totally dry rotted. Plus their cheap enough, you might as well replace them anyway if in doubt.
I'd also replace the fuel pump relay while your at it. They are a known much too common problem in our trucks. When mine have gone out in the past they act like you're saying. Eventually it would start, but for me one day it never would fire. I had no fuel to burn after all.
