every thread about no start situations talks about tach movement. my 1996 e350 7.3 has no tach in the dash. i understand the pcm does not even support a tach signal in vans? i read somewhere that the pcm for vans does not even have a pin to support a tach,but yet the pcm needs a tach signal to see 200 rpm to start? how could i get a tach for this?

 

same question here

 

You should see it through a monitoring system. Something like the torque app or ae. If the pcm doesn't know the rpm then it also won't know when to inject fuel

 

sounds fair enough. i wonder why every 7.3 van i have ever seen does not have a tach. is there an aftermarket system available to add a tach? like a simple reflective tape/sensor type?

 

The vans are different in a lot of ways, mostly because they are not intended to work as hard as a pick-up would be worked. You really don't need a tach in a van. Sure lots of guys want one, but it's not like you are climbing a mountain with a huge RV behind you and you want to watch rpm's to change shift points, etc.

The van PCM for sure knows rpm's, you can add an Aeroforce Scangauge that not only shows rpm, but shows a lot of other useful data, as well as buzz, CCT, and code reading/deleting capabilities. I have them on the shelf, if you are interested call or email us.

 

but this used to be an ambulance. 1 ton chassis with 4.10 gears, dana 80 rearend, every cooler imaginable. pulls like a freight train when running. just stops like you turned off the key too often. checked ipr tonight. tin nut was plenty tight. not knowing how to bench test ipr, checked ohms across the 2 terminals. on the 200 scale it read 34-35. seems high to me. also, on the small diameter end that goes into pump,there are 2 small o-rings. one round and the other square. the square one is torn. could that cause this much of a problem?

 

Ambulance is still not the same as a pick-up towing heavy.

If it just randomly shuts off and fires back up when you crank it, that's the CPS.
The O-rings you see on the IPR sound correct. The one is cut at an angle and not really torn. Look again. If it is actually torn, you'll want new ones, but I'll bet it's an open o-ring with the end cut at an angle.

 

it would randomly shut off and always restart, but it might start right away, in 15 minutes, 2 hours or the next morning. purchased a new ipr today. the square cut o-ring is not cut at all and the resistance is only 12.8 ohms compared to 34ish on the old one. i hope i am on to something. i replaced the cps with the gray one from IH and that did not solve the problem. if the problem still persists, i will have to check wiring i guess, but the connectors and wires all look fine.

 

You'll need to monitor the High Pressure Oil system pressure while cranking when it dies and won't re-start. If pressure is under 550 psi or so, then there's an issue with that system and that's the next thing to investigate.
If pressure is good, that eliminates the pump, IPR, injectors, etc.