Bought a Actron scanner today, the $24.99 special. The SES blinks this: flash, flash, flash, pause...........flash,flash,flash,flash. The book really doesn't say what this is. Take a flash off the first series and it becomes a 24. With that extra flash, does that make it a 25?

Thanks,
Brandon

 

It's a code 34. In my case, MAP sensor problems. Voltage is too low. Would that cause the fuel pump not to prime as well as the engine not to even crank?

Update: Just went to the car and disconnected the ecm and noticed some teeth missing from both the connectors. Is there supposed to be?

Brandon

 

What car is this?

The codes have different meanings depending on the system that's installed.

 

My 1984 Iron Duke SC. Car won't crank, fuel pump won't prime and it's dishing out code 34s. Hooked up a 83 Z CFI ecm and it only dished out code 12s (not that it would work anyway).

Brandon

 

That's a '34', and on the mighty 151 it means the vacuum/MAP sensor reading is too low at at a given engine RPM and throttle opening. It should not prevent the fuel pump from running, nor the engine from starting. You have other issues with the fuel pump.

The burning question I have is whther your four-holer has the E2SE carburetor or the TBI300 injection unit. The carbed engine uses a different (mechanical) fuel pump and different control scheme.

If you have the TBI injection system, I presume the pump circuit is similar to later cars, in which case you have a pump/ECM fuse under the hood (near the battery) and a relay on the firewall in the engine compartment.

For either system, engine cranking is controlled by the ignition switch, the clutch/neutral safety switch, and the starter solenoid.

The ECM for a CFI should not be the same as for the TBI300 nor the E2SE.

 

It's a TBI engine. I'll check the ignition switch, etc. Thanks! But....I don't understand how it could pop out a 34 when the engine's not even running. My bro-in-law has a Fluke tester. He checked the starter out on Sunday. There was voltage going to the starter. If the solenoid is out, wouldn't the fuel pump still prime? Another thing, when the ignition was turned on he detected voltage going to the ecm. Would a bad ignition switch or clutch safety switch cause the fuel pump not to prime. I have a hunch the fuel pump and not starting problem are related.

BTW, I did check out the wiring under the column...everything appears ok.

Brandon

 

A couple questions.....

If you disconnect the ecm all together...the engine should still crank, right? The fuel pump, relay were replaced last year. Bad ecm?

Since Vader mentioned the clutch/neutral safety switch, I do recall the last year of having to release the clutch and re-engaging sometimes to start the car. I found this white thing mounted on the left side of the steering column with a rod going up into the column. What is that? Whatever it is, I can't get it to engage.

Brandon

 

Guess I'll just replace the ecm, ignition switch & neutral safety switch and hope for the best.

 

That "white thing" on the left side of the column - is it down under the dash, along the top side of the outer column tube? If so, that's your ignition switch. If the linkage rod doesn't move with the ignition key/lock cylinder, I think you've found your problem.

 

No it's on the left side of the outer column with a rod going to it. I found the ignition switch on the top of the column, the rod moves like it should. Did find a possible bad harness neutral safety switch. I'm thinking the ecm is bad, since it's spitting code 34 with the engine off.

Brandon

 

84,

First, error codes are stored for the last 40-50 engine run cycles. If you're getting a '34', it's because the error was generated within that time.

Second, error code retrieval should ALWAYS be done with the engine off and ignition ON. (NOT running). Jumpering the 'B' and 'A' pims while cranking the engine can damage the ECM.

Third, if the ECM is reporting error codes, it is probably NOT defective. If you got nothing (even a '12'), I would suspect an ECM problem.

Finally, the in-tank fuel pump is controlled by a relay. If the relay or connections are faulty, the pump will not operate. The pump is supposed to run for two seconds when teh ignition is first turned ON (to prime the system). The pump will not operate again until the engine is cranked, or the ignition is turned off for at least 20 seconds, then tunred back on, whereupon you'll again get the two-second prime cycle.

Make sure the pump relay is intact. Make sure the relay has power and the relay operates when the key is first turned on. Check back with results, please.

 

Dang Vader! Sounds like you really know your stuff.

I don't have any means to test my fp relay. The relay is brand new as well as the fp. Since the engine won't even crank, I suspect the problems are related. I did remove the ignition switch a little while ago. The rod does move like it should. Is there any other way to tell if an ignition switch is bad?

Brandon

 

That's the headlight dim/bright switch. It's not the problem.

Don't overcomplicate things. First, find out if the car will run if you supply it fuel some other way, by spraying starting fluid into it or something.

If it does, then you have a fuel delivery issue. If you hear the relay click but don't hear the pump running, and you have a new relay, you most likely need a fuel pump. It's possible your wiring is bad, but that's pretty unusual.

 

Fuel pump won't prime. Hell!@ It won't even crank! I'm hoping it's just the ignition switch.