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4.9l ford no start

I just fitted a '93 4.9l from an E-350 into my "79 F-100. I used the '93 ECC and harness with relays and fuses and "tapped" into the '79 fuse block and chassis harness. I installed the tank and high- pressure lines from the "93 and all went in perfectly. That is until I went to start it. I have power to all systems and the engine cranks, fuel pump comes on, I have pressure on the fuel rail, I have spark, and even my back-up lights and neutral safety work properly, but the engine does not start. I wired in the following sensors: HEGO, MAP, TFI, and TPS (am I missing something else?). I have voltage on both leads of the injectors during crank and run. I am not certain if this indicates the ECC is controlling the circuit. I believe the ECC controls the injectors through two wires (white for

123 and tan for 456) and these wires are grounded by the ECC when each of the respective cylinder fires. I can start the engine by spraying a little gas into the throttle body, but otherwise, I am not getting any fuel through the injectors. I have a couple suspicions: I did not use the vehicle speed sensor system. (I don't think this would matter at start-up), or I have blockage at the injectors (The system sat open for about two years). Help !
Reply to
scebay
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Reply to
dahpater

Does the Vheicle speed sensor need to be hooked up? Should I jumper the wires on the EEC (#3 to #6) if I did not connect the VSS?

Reply to
scebay

No & no. The speed sensor won't keep it from starting/running. Speed sensors are used for speedometers, fuel trim, cruise control, and trans shift points.

Reply to
dahpater

Having retrofitted a 5.0 EEC-IV system to a 351C, I know that the VSS is not essential.

You say that the fuel pump comes on. Does it stop after about two seconds or does it run continuosly with the ignition on?

If the pump stops, then the EEC is alive. If it runs continuously then the EEC has crashed.

My guess is that there is a problem with the wiring from the distributor/TFI to the EEC. The EEC needs to get the PIP signal from the distributor to know that the engine is turning and to time the injectors.

The TFI can generate spark with the EEC dead, so the fact that getting it to run by spraying fuel manually doesn't mean much.

You fail to mention the ECT and ACT sensors, but none of them are essential to start the engine.

The EEC can run with most of its sensors missing, and it can even run with the processor dead. It goes into LOM mode, where there is analog electronics that generate a fixed 50% injector duty cycle and you modulate engine speed with the amount of air passed by the throttle. It will still need the PIP signal from the TFI though

Reply to
Thomas Tornblom

Do you have a good ground path from the computer to the engine?

Are all the computer harness grounds bolted onto the block? Usually near the dipstick? I have seen one dropped wire there too many times on engine swaps.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail > I just fitted a '93 4.9l from an E-350 into my "79 F-100. I used the
Reply to
Mike Romain

On Jun 13, 8:57 am, Mike Romain wrote:

To all, for your responses...Thank you...I purchased a set of niod lights and determined that I did in fact have a flashing light at all of my injectors...with 60 psi fuel pressure on the rail, this mother should start...But no..The only thing left to check was the injectors themselves. As I am a meticulous fellow, I checked and double checked every wire from every sensor to the ECC and elsewhere, before I wrapped the new harness. I was certain I did not leave anything out. I had fuel (to the rail), spark , crank, everything should be correct (after all this is not rocket science. If a guy can read a schematic and follow some lines and wire color codes these EFI swaps are a snap...) So....This afternoon I pulled the fuel rail and injectors and using a battery and a couple test leads I attempted to manually open the injectors and none of them worked.!!! thirty minutes in a denatured alcohol bath and compressed air in both directions with power to the injectors I had them all working just like a song. I re- installed them and replaced the upper manifold, and viola!! The engine fired and purred like a kitten on the first crank....Dirty, stuck injectors...Who would have thought??? All problems solved... This was a cool project...Next...My "65 Ford short box step-side will be getting a '95 EFI 351W can't wait to get that one going....Hopefully I'll find all the parts I need before the end of summer and I have to go back to work:)

Reply to
scebay

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