94 powerstroke with code 841

[jbarnett31]

Ive got a 94 with the first powerstroke in it, customer states it dies while driving and wont restart. It has code 841 for icp steady state error. The pin point test only gives steps for an unstable idle, this one has had a pretty stable idle since I have had it. I have not duplicated the concern yet. I manually checked the oil pressure and at idle its at 700psi. I have not done much else to it yet but I am not real familiar with the old eec iv set up and was wondering if anybody had any help or suggestions for me to try tuesday morning. Thanks

[cbriggs]

I thought all powerstrokes were eec v? with an obd2 connecter under rh side of dash.

[Brad Clayton]

The very first ones were equipped with both. The OBDI connector was under the hood on the drivers fender. You can reflash the PCM and it will update to OBDII and then you can actually have some better info to work with using the OBDII connector under the dash.

 

One of the drawbacks for the customer back in the day with these things, the customer had access to a selectable RPM function. It was very user friendly and you could put the RPM just about anywhere for using PTO's and what not. After updating the PCM, this would go away and then the customer would have to purchase the 'ol APCM.

[Keith Browning]

Though not very complex those engines can be a bear to diagnose because the diagnostics are basic AND the PCM does not give you true readings through the scan tool. In this situation I would give the pinpoint tests for the DTC a try and when you get nowhere use your head. If you know you have an ICP/IPR issue, look up the pinpoint tests for both, read them, then hook up your Break-Out-Box and perform those tests from the beginning using your measurements from the BOB and your meter, not the scan tool.

 

I learned this the hard way. Here is one such example ---> Lying PCM

[Bruce Amacker]

Ditto on what Keith said, I'd also suggest putting a (new/reman/used) PCM in it so you can talk through the OBD2 connector as you frequently cannot flash these to '96 specs like FMC says you can. (I'm assuming you're talking through the EEC4 underhood connector and not the OBD2 under the dash) It's odd it has not been updated as almost all of them have been by now.

 

Monitor ICPV while driving and don't forget the HP system depends on LP oil, you might want to check that at the port on top of the reservoir while you're driving. I'm frequently seeing HP oil problems on older 7.3s from the LP system dropping out. The oil gauge on the dash is a liar, you know.

 

A Fluke can be used to monitor IPR command, it should be 9-11% at a hot idle and ballpark 30-50% while driving. If it pegs at 85% it's starving for HP oil (or LP oil).

 

Good Luck!