Help with a 97

[Freightshaker]

97 OBS
-was shut off and restarted an hour or so later and ran terrible
-according to a infra red gun it is only running on one cylinder.
-passenger side has the 1 firing cylinder and driver side dead.
-valve cover gasket harness had oil in it when unplugged.

That's all the info I have right now. It is a family member of my wife. I told them to pull codes and they said / low voltage/ and throttle position. (sorry that's what they told me) Any tips are appreciated.

 

[Denver]

How's the oil level and does it have fuel?

 

[Freightshaker]

Yes, and yes. I'm leaning electrical because it happened sudden.

 

[Arisley]

Does the OBS have a connector on the driver side valve cover, like us Superduty guys do?

If so, that's the first place I would look.

You cans also:
1. Look at a wiring diagram
2. Pick a pin on the valve cover end and attach a multimeter lead to it.
3. Refer back to the wiring diagram and figure out which pin it is on the IDM connector.
4. Ohm between those two pins.
5. Check all connectors until you narrow it down to a certain section of connector.
6. If it is a connector, repair, or replace it. If it is a section of wire, replace the section of bundle, or locate the open or short, and repair it.

 

[Freightshaker]

I have this one. I have not really worked on obs but I'm sure they are similar enough. Hopefully I can look at it tomorrow.

 

[d7es3l]

Does it have a chip? Or all stock?

 

[ghohouston]

Does the OBS have a connector on the driver side valve cover, like us Superduty guys do?

If so, that's the first place I would look.

You cans also:
1. Look at a wiring diagram
2. Pick a pin on the valve cover end and attach a multimeter lead to it.
3. Refer back to the wiring diagram and figure out which pin it is on the IDM connector.
4. Ohm between those two pins.
5. Check all connectors until you narrow it down to a certain section of connector.
6. If it is a connector, repair, or replace it. If it is a section of wire, replace the section of bundle, or locate the open or short, and repair it.

yes, it has the same 42 pin connector, but extends more towards the fender well where the 2 connectors meet. for whatever reason, the obs's didnt utilize the bracket of the valve cover that the connector slides into on the sd's.

 

[Freightshaker]

Does it have a chip? Or all stock?

All stock.

 

[ghohouston]

have they pulled the valve covers yet, or just the connector on the engine harness to the valve cover gasket? sounds like the uvch could have come unplugged or burned up. for some reason obs harnesses seem to like to melt... can they run an injector buzz test?

 

[Freightshaker]

have they pulled the valve covers yet, or just the connector on the engine harness to the valve cover gasket?
-just the connector

sounds like the uvch could have come unplugged or burned up. for some reason obs harnesses seem to like to melt...
-kind of what I'm looking for, a good notorious place to start when I get there

can they run an injector buzz test?
-I don't believe they can

$$$

 

[Rubyred]

sounds like maybe the oil caused an electrical problem. what caused the valve covers to fill with oil?

 

[Freightshaker]

Pulled valve cover on driver side. Checked outside of valve cover connection to ground and to injector plugs. Seemed ok. Checked valve cover plug to female side of 42 pin and everything ok and with nothing to ground. I suppose all that is left harness wise is to check male side of 42 pin to idm. All connections look ok with nothing corroded/burned/loose. I quickly learned my above schematic is for superduty.

 

[Arisley]

Yep, and that is a really good schematic for the Superduty.
I have a one of those that is two pages, I have it laminated.

 

[m j]

charge the battery, replace the UVCH and valve cover gaskets

I do not believe it would run on 1 cylinder

 

[Freightshaker]

I think I figured it out... too many black ice trees hanging from rearview mirror.

Teenagers lol

 

[Arisley]

That will do it. Truck just gets fed up and says FU.

 

[Freightshaker]

Will perform highly scientific wiggle test on harnesses tonight. Think I found someone with a borrowable IDM on the shelf also.

 

[gnxtc2]

Do NOT plug in the borrowed IDM until you remove the valve covers and inspect the UVCH. If they are burnt, you might short out the IDM. YEs, the IDM has circuitry to self protect itself but why take a chance.

The OBS trucks have two plugs on each VC gasket. Usually the GP pins burn and take out the injector pins.

Billy T.
[email protected]

 

[Freightshaker]

Good point.

Last night I mapped out the plug on the back of IDM. Drive side injectors ohm out 3.2-3.3 from the idm plug. I have not pulled passenger side valve cover but that is what it runs on. Wiggled everything with no changes. Should get a scanner on it tonight. The spare IDM had water dripping out of it so that's not good.

 

[Smokinstrokin7.3]

My 96 had the same problem started one day then the next day half the block was down. Thought I blew injectors, ended up being my valve cover harness connections they had oil in them and the connectors melted. Replaced both sides and the glow plugs since it was already apart. Try it out one little burn wired can shut it down.