ignition system on 5.8l v8 engine problems

[11harris11]

Hello
I’m in need of serious help

I have being doing a massive diy on this engine and I am now stuck. i have a 1994 5.8L EFI ford 351w engine. This was fuel injected and TFI ignition controlled.
The problem I am having is that the ecu had sea water damage and is completely un-repairable or un-purchasable.
This lead me to convert the engine back with new intake and 600cfm Holley carb.
However I am now getting no starting and inconsistent backfire. I think the ignition timing is all off.

Is the TFI ignition controlled by ecu?
Would the broken ecu course a backfire through carb?
What simple choices do I have of replacing the ignition system?
Is a HEI ignition system the next best step for myself?

If anyone could answer any of my questions it would be very very very much appreciated. Thank you.

[stevieturbo]

You would expect a single ecu to control fuel and sparks. That is normal.

Without more specific info..hard to say, but at a guess that engine could well have a 36-1 trigger wheel on the crank. If so you could fit a megajolt ignition system to it which would give good control and good value.

What was the makeup of the ignition system previously ? Multi coil, dizzy, what ?

If dizzy, surely somewhere makes a simple old mechanical dizzy setup for the engine that would just install and work ?

[unstable load]

Speak to the Megasquirt guys about that. You should be able to keep it injected if you wanted to.

[DaveEFI]

Hello
I’m in need of serious help

I have being doing a massive diy on this engine and I am now stuck. i have a 1994 5.8L EFI ford 351w engine. This was fuel injected and TFI ignition controlled.
The problem I am having is that the ecu had sea water damage and is completely un-repairable or un-purchasable.
This lead me to convert the engine back with new intake and 600cfm Holley carb.
However I am now getting no starting and inconsistent backfire. I think the ignition timing is all off.

Is the TFI ignition controlled by ecu?
Would the broken ecu course a backfire through carb?
What simple choices do I have of replacing the ignition system?
Is a HEI ignition system the next best step for myself?

If anyone could answer any of my questions it would be very very very much appreciated. Thank you.

Think the timing is controlled by an ECU. And that it may need an extra signal to control the cranking time. Again IIRC it can be controlled by MegaSquirt

[garrycol]

Being a mid 90s American Ford V8 basic ignition would have been provided by EDIS 8 controlled by an ECU for both ignition and injection. As such there should be an appropriate trigger system for EDIS 8 and the ECU - so the lot should be easily converted to MS as a replacement for the ECU.

[DaveEFI]

Not an expert, but think the TFI system is earlier than EDIS. Sort of a halfway house between the old purely mechanical dizzy and current systems. The advance curve is mapped by electronics - rather than springs and weights. But still with a single coil.

If it were mine, I'd certainly go over to a crank trigger and wasted spark. But then I'd not be changing back to a carb, either.

[stevieturbo]

Even if he did only want sparks sorted...it would make a lot of sense to consider buying a full ecu...at least then going back to efi would be an easier task some time in the future.

[DaveEFI]

Even if he did only want sparks sorted...it would make a lot of sense to consider buying a full ecu...at least then going back to efi would be an easier task some time in the future.

Yes. I'm fairly certain MegaSquirt can control TFI - but MegaJolt only EDIS?

[stevieturbo]

Even if he did only want sparks sorted...it would make a lot of sense to consider buying a full ecu...at least then going back to efi would be an easier task some time in the future.

Yes. I'm fairly certain MegaSquirt can control TFI - but MegaJolt only EDIS?

Dont care what system is fitted at present....either would control sparks for him as a retrofit. And given Ford and age of car it's bound to have a 36-1 or some sort of usable trigger system for a range of ecu's

[11harris11]

Hello thanks for all your reply’s.

After doing a few test it is the ignition timing that is all wrong.

A new EEC Is nota option, I’ve taken it to specialists and they all have said it was done and can’t find another one as it came from a boat and its map is nowhere to be found. That’s why I went to a carb.

So I’m going to need to fit a whole new ignition system in. And by the looks of it the HEI looks the quickest and simplest to install? I may be wrong ha

Thank you very much for all your helpful replies!!!!
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[DaveEFI]

Hello thanks for all your reply’s.

After doing a few test it is the ignition timing that is all wrong.

A new EEC Is nota option, I’ve taken it to specialists and they all have said it was done and can’t find another one as it came from a boat and its map is nowhere to be found. That’s why I went to a carb.

MegaSquirt etc are universal aftermarket ECU and you can create your own map - or load one for the same engine, if you can find one. Which may actually be easier than tuning a carb from scratch.

So I’m going to need to fit a whole new ignition system in. And by the looks of it the HEI looks the quickest and simplest to install? I may be wrong ha

Thank you very much for all your helpful replies!!!!
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If having to fit a new system, would make sense to go for the best available? Anything dizzy based has all the reliability issues of such systems. And is never going to perform as well.

[stevieturbo]

I guess whatever dizzy he wants to use is simple. Bolt in new part and run. No messing, very little wiring, no real work or effort ( or cost ) required.

I would also highly doubt he needs the best available either...that's really going to the other end of the spectrum, when there re many budget options he could go for too.