I second that.Have you looked at your ignition switch under the dash for a burnt connector?
I will look into and report backHave you looked at your ignition switch under the dash for a burnt connector?
Just to make it clear, misfire is cause by revlimiter cause rpm reading goes nuts.Ok so other than MS it's stock.
So what I'm getting is at or around 3k rpm,
If you turn on a load ( blower) you get a misfire and the rpm reading goes nuts.
If no electric loads does it misfire?
When it does misfire, which cylinders?
I suspect o short to power. But some things need to be eliminated. Have you connected the condenser to the coil? If not, do that first. Also is the shielding in the tfi harness intact?
I've done a similar test (without condenser) spare electric fan straight on the battery and I repeat the behavior.So here's a test. Once the condenser is connected take either your blower out or use a spare, with the car running, connect the blower directly to the battery with jumpers or a power probe if you have one.
Does the symptom return? If no, then you have a short in the dash harness and i would definitely check the ignition switch.
Do this and report back.
I could turn off rev limiter and that will stop spark cut but will still have pip signal messed up.So really it's the crazy rpm pip signal input to MS that triggers the rev limiter. Have you tried turning the rev limiter off.
I'm sorry if I'm not getting everything, I'm not there so diagnosis over a forum is difficult at best.
I'm not sure jumping eec relay will give me power to TFI and coil, will have to look schematic. Several things to try in the next days. I want too to remove all wires from EEC harness that are not needed to run engine. (Speed aensor, pressure sensor, etc)Try this.
Leave the key off. Make sure your in park or neutral.
Find the eec relay and jump it on.
This will power on everything needed to run engine. Jump the starter solenoid to start engine. Does the symptom return?
What i want to see is the system running and not connected to key on power.
Also the condenser does more than just cut emi from the radio. This still sounds like a short to voltage.
Now this is important to note. I have had a fair share of running my tail off chasing running problems only to come down to multiple faulty tfi modules.
What is PNP? I live Canada and checked.on Amazon and Rockauto, and dont find. Still looking. Any part number?Oh and you can get the condenser off any tfi ford. PNP is full of them.
Ok for PNP, will look into.PNP is pick n pull wrecking yard.
SO, what this has come down to is a bad pip signal.
You see this by scoping the pip at the tfi module.
When i look at the scope capture I'm seeing a failure of the pip signal. The signal is losing its proper waveform and giving just enough of a signal to make the ecu think it's a higher speed.
This seems to be aggravated by a high electric load.
You said if alternator was disconnected the symptom goes away, but you've tried other alternators.
I fail to see anything causing a corruption of the pip at the output of the module. I know that scoping the power to module you get noise. But what's the sweep of that voltage? The system can handle quite a bit of that and still run fine.
I had my truck start misfire and stall after about a half hour of running and the hotter it got the worse it was, leaving me stranded for hours. I replaced the tfi module, the distributor and coil and nothing helped.
When i scoped the ignition i captured the voltage, pip and coil trigger.
What i found was voltage was dropping as it warmed up and eventually dropping to near zero. Turned out to be a coroded wire and the ignition power splice.
Around 9 volts the ignition started cutting out. The pip would randomly drop out from lose of voltage.
My point is i learned what the system can handle in terms of voltage.
If you remove circuits from the ecu, don't cut them just remove the pins from the connector. You might want them later.
When the symptom happens and you get a bad pip and noisy power, is this also at the positive battery terminal?
I do understand the purpose of that test and will look into.Yes if you turn on eec relay the ignition is also powered. What this test is doing is isolating the engine system from other key on accessories
No, I'm not, its late here (UTC-5)I'm currently at work so i might be slow at responding. Are you currently working on your car?
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?