Cranking problem

[JimC]

IÂ’m looking for some suggestions for a cranking issue I have developed. This is a stroked 351 with a FiTech 600. Early on I had a problem with a map sensor gasket resulting in bad readings when the engine reached operating temperature that resolved once I corrected the gasket issue. So IÂ’ve driven 2000 miles since then with no issues until this problem came up. When I key on the fuel pump starts up and runs for 10seconds or so with fuel pressure reaching 60 then the pump stops and pressure drops to about 40 and holds until I start cranking the fuel pump starts back up and pressure rises to 60 for as long as I crank it. When the engine was cold it would crank easier if I keyed it on three times before cranking, when warm it would fire easily keying it once. This past week I had to key it on multiple times and crank much longer to get running, once it was running it ran fine for a 3 hour trip and cranked fairly easily when hot. Since that trip I cant get it to crank or fire at all. I have spark and fuel pressure. FiTech support had me reboot the settings to the factory default and I added a ground to the throttle body, but no change. All the in line fuses on the Fitech wiring look ok. The hand held monitor shows map of 98 and rpm 140 to 150 when cranking. I pulled the air filter and cannot smell any gas. Sorry for the long post, IÂ’m a newbie and not sure which of these points are pertinent. Thanks

[phileas_fogg]

Have you tried giving the car just a little bit of throttle (~10%) when cranking? Don't give it more than 30%* because the FiTech software will think the engine is flooded & not fire.

If that doesn't work, take the air cleaner off and have a friend crank the engine while giving it 100% throttle. CAREFULLY peak down into the throttle body to confirm the injectors are firing; you should easily see the stream of fuel. I say "carefully" because if the car starts & you get a backfire, you might get singed.


John

*The 30% threshold is from Holley; I don't know what FiTech's threshold is but it's almost certainly very close if not identical.

[Norm B]

You don’t have your location indicated anywhere so it this is just a guess. Has the temp got colder in the time that your starting problems have occurred? If so, go into your setup and add fuel to the Start and Warmup setting. I screen shotted the instructions from the Fitech website.


HTH

Norm

[JimC]

I appreciate the advice, I’m outside Atlanta and in an enclosed garage so I don’t think temperature change is significant, I tried adding fuel through programming with no luck. Observing while cranking and giving throttle I can’t see or smell any gas. Fitech support sent a zip file to reboot the ecu with no change, they are recommending I send the whole unit back to them. I guess I will, seems the problem is in the unit itself but I wanted to be sure I had checked other possibilities first. Thanks

[RBachman]

Jim, I've been through these same symptoms with FiTech before. First hard to start, then no start. For me I believe the issue was a failing ignition module. This can really freak a 600 out. I also tried a couple different coils and it made no difference. But I do have a couple spare coils now. LOL I got it running again after replacing a Pertronix II ignition module. If you're using an Ignitor II or similar this would not surprise me.

If you like, PM me a number and I can go into more details. But also check out the FiTech users group on FB. LOTS of great advice there.

[JimC]

I’m still trying to figure out where my problem is. I have found a few clues but I can’t put it together. It appears I have some problem with voltage. The battery has 12.4 volts and drops to 10 when cranking by my hand held volt meter. The Fitech hand held shows 12.4 but jumps all around while cranking from 6 to 9 volts. If I put a 50 amp jump from my battery charger to the battery I get a steadier reading and a little higher value and the car cranks up and runs . Also when I key on without trying to crank my tach on the dash bounces around without the engine turning over, the hand held show no rpms at the same time as it should. Anybody have any suggestions?

[JimC]

Scratch that bit about the tach jumping around, I think that was happening only with the battery charger attached

[sread]

Not familiar with Fitech system but Holley specifically cautions against never cranking the engine with a battery charger connected, especially on "boost " setting - can damage the ecu

[rich grsc]

I’m still trying to figure out where my problem is. I have found a few clues but I can’t put it together. It appears I have some problem with voltage. The battery has 12.4 volts and drops to 10 when cranking by my hand held volt meter. The Fitech hand held shows 12.4 but jumps all around while cranking from 6 to 9 volts. If I put a 50 amp jump from my battery charger to the battery I get a steadier reading and a little higher value and the car cranks up and runs . Also when I key on without trying to crank my tach on the dash bounces around without the engine turning over, the hand held show no rpms at the same time as it should. Anybody have any suggestions?

That is a bad battery or bad connections.
No EFI is going to properly start and run without full voltage.

[JimC]

I appreciate the input, I tried another battery, I’ve got 12.4 volts everywhere with key on, battery drops to 10-11 while cranking. I checked the volatage on the battery feed wire where it enters the throttle body and get a steady voltage of 10 or better while cranking but the handheld moves between 5 to 9 while cranking. Resistance on the battery feed wire and ground
wire I added to the throttle body are low.

[phileas_fogg]

That seems to imply that there are other circuits active at cranking, drawing current & sucking your voltage down. So...what other circuits (RUN & CRANK) are active when you crank the engine? Maybe start by pulling all the ACC fuses + non-necessary RUN fuses & adding them back one by one?


John