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Old 03-29-2016, 12:30 PM   #1 (permalink)
CampVan
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Stalling: Ground locations on 6.5 1997 Express van

New to the forum, spent an evening going through the wealth of informative postings to find help with the latest phenomenon in my new-to-me 6.5 1997 Chevy Express van. I'm not very mechanically gifted and on a steep learning curve with this van project; Previous owner made many mods, including computer delete, DB2 injection pump, vacuum delete/spring loaded waste gate, 4WD, manual transmission, 2 electric fans instead of stock fan, custom instrument cluster with pyro and boost but no rpm gauges, relocated all fuses from 2 panels in engine and driver foot panel to one in passenger side dash, ...

The coolant temp gauge went off after the needle 'danced' for a couple hours on a road trip last weekend that also included some bumpy dirt roads. A few hours later after taking off from a fuel stop the engine stalled at a red light.

Starts and drives fine but stalls now every time the rpms go down to idle. Except if I manage to shift down and decelerate very carefully and bring the van to almost a stop in first gear. At least a couple of times the idle then held without stalling.
I read on this forum that the two events (engine stall and temp sensor turning off) could be related to a faulty ground, and that there are several, that should be cleaned. Happy to do it as maintenance, but also would like to avoid a goose chase, open to other guidance to get back on the road and home ;-)

I only found one engine ground cable so far, going from the van's passenger side battery under the hood behind the lights down to the engine, and to the frame. Hard to reach but I'll try. (The other battery is on frame under the van, a little behind driver door.)
Where are other ground locations, seems different on the van?

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Old 03-29-2016, 12:45 PM   #2 (permalink)
HeavyChevy95
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More likely a fuel supply problem than faulty grounds. Not at all familiar with vans arrangement, much less one with so many changes..

FWIW Fuel Supply System Checks

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Old 03-29-2016, 01:01 PM   #3 (permalink)
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The factory coolant gauge sender is on the driver's side head located above the #1 cylinder injector. I would check the connector and the wiring.

Check the Fuel Shut Off Solenoid to make sure it is working correctly. Worth downloading the 6.5L Turbo Diesel DB2 Student Handbook. A link to this Handbook is in HeavyChevy95's signature above.

Gotta wonder how the PO has the lift pump wired to run. Is there a fuel pressure gauge in the van?
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Old 03-29-2016, 01:36 PM   #4 (permalink)
CampVan
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Thanks Heavy, I was just reading your excellent writeup on fuel system checks you posted to tpetty a moment ago. If it helps diagnosis: this van has 2 fuel tanks, 1 stock and 1 aux, each with independent lift pumps. Lines meet just before the IP. So for roadside diagnostics' sake I start looking for other clues as the supply up to the T-solenoids before the IP, and the respective returns would be surprising to fail or have a blockage on both sides at the same time.
I'll look for kinked lines next.

I feel this issue is a little different from a fuel supply problem I had recently. The supply fitting at the IP did have a loose connection a couple of weeks ago drawing in a little air over night so it would stall after the first cold start in the morning but fine when starting warm later.
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Old 03-29-2016, 01:51 PM   #5 (permalink)
CampVan
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Thanks Freddy,
I looked at the coolant temp sensor yesterday evening and the red wire and connection seem stock and fine. I only followed the wire a foot or so until it merges a wrapped bundle of wires as I hesitated to unravel all these, what do you think?
This sensor only had one wire. A sensor on the rear passenger side corner of the engine visible when opening the doghouse inside the cabin has two wires; I assume it is the oil pressure sensor, that gauge works fine. That's why the ground fault theory made sense to me which I read in a posting.

I downloaded the DB2 handbook and will try to read, a little tight on my phone screen.

I am not sure how the stock lift pump is wired, I do hear/feel a pump from the inside of the stock tank if that makes sense.
Perhaps unrelated: there is a 'minor' fuel supply issue in the stock tank, as I noticed in the past twice it cannot start when parked facing uphill with less than 1/3 diesel in the stock tank. It's fine when flat/downhill, I keep this tank more than 1/3 full for now and was planning to ask a question when I get home about dropping that tank and looking for possible clogged sock or delamination. Thoughts?

I did change the stock diesel filter and cleaned out the aux tank, lines and filters last week before starting on my first road trip.

Last edited by CampVan; 03-29-2016 at 02:08 PM. Reason: adding more info
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Old 03-29-2016, 02:29 PM   #6 (permalink)
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Whats the 8th character of the VIN, not that it makes a difference but it may tell us if this is a complete conversion of just a DB2 conversion.

Thoughts..... All the diesel models use an externally mounted lift pump ACDelco EP 158 just forward the fuel tank. Usually mounts where the fuel filter would normally be located on gasoline models. If its still has the gasoline filter and fuel pump in place, might explain a few things..

If your liftpump is inside the tank, its likely the wrong one and its got the wrong strainer(sock) on it most likely.

Last edited by HeavyChevy95; 03-29-2016 at 02:31 PM.
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Old 03-29-2016, 02:52 PM   #7 (permalink)
CampVan
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8th VIN character is an F
Yes it has a small cylinder that could be a liftpump mounted on the forward edge of the tank protective cover. I did not feel/hear vibration from it when I familiarized myself a bit with the van after purchasing it a month ago. At least it sounded like coming from inside the front of the tank but I could be wrong. I can clearly hear it even inside the cabin when turning ignition on.
The aux tank lift pump looks similar. It is wired to a switch that turns either the stock pump or the aux pump on and the other off, and seems to change the flow at solenoid Tjunctions before (and probably aft of) the IP.

Sorry for challenging y'all with the PO's mods, thank you for goodwill helping regardless; in the last month I already suffered the glare and rejection by standard mechanics, most of whom seem to be capable to swap stock parts but refuse to try helping with common/mechanic's sense.
Just as a word of context: I bought this van and thus entered your Chevy6.5 world coming from the scary underworld of the Ford6.0. As I plan on doing a South America road trip some time next year, this van, which the PO whizzkid so craftily simplified, appealed to my layman's eyes as I thought it could be more easily troubleshooted in countries where none of the US-made vans were ever sold and thus computer diagnostics would be hard and parts unavailable. So my local road trips are testing that thought right now ... ;-()

Last edited by CampVan; 03-29-2016 at 03:02 PM. Reason: 8th VIN character is an F
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Old 03-29-2016, 04:07 PM   #8 (permalink)
CampVan
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Took too long to double check so exceeded the time the forum seems to give for editing my above post, so posting a correction:
The stock lift pump IS in fact the one working outside forward of the stock tank, I must have misheard the sound as coming from further back inside as the vibration travels on the plastic tank shield. It is alive and pumping.
Will now start taking off the doghouse and report later if I find kinks.

FWIW regarding the grounds theory: seems the starter battery(ies) were a little weak to start this morning. That's the first time. It did start after 10 sec cranking (normally she starts right up on the first crank since I changed the glow plugs and relay last month and replaced the manual momentary hold switch the PO installed instead of the gp ignition key position) with the help of the 4 deep cycle camper batteries in addition switched in series.
Still same idle dying, except if I bring the idle down gently in first gear to a halt using the handbrake (I know I know, that handbreak's another mod ;-)

Last edited by CampVan; 03-29-2016 at 04:10 PM. Reason: typos
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Old 03-29-2016, 04:16 PM   #9 (permalink)
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Quote:
Originally Posted by CampVan View Post
Thanks Freddy,
I looked at the coolant temp sensor yesterday evening and the red wire and connection seem stock and fine. I only followed the wire a foot or so until it merges a wrapped bundle of wires as I hesitated to unravel all these, what do you think?
This sensor only had one wire.
That is the right sensor. And it only has one wire. The sensor grounds via the engine block.

Quote:
Originally Posted by CampVan View Post
A sensor on the rear passenger side corner of the engine visible when opening the doghouse inside the cabin has two wires; I assume it is the oil pressure sensor, that gauge works fine. That's why the ground fault theory made sense to me which I read in a posting.
.

6.5L blocks have the Oil Pressure Switch on the drivers side behind the head or located in the back of the valley below the lower intake manifold.

If you can post some pictures of what you are seeing that might help us.

Quote:
Originally Posted by CampVan View Post
I am not sure how the stock lift pump is wired, I do hear/feel a pump from the inside of the stock tank if that makes sense.
Perhaps unrelated: there is a 'minor' fuel supply issue in the stock tank, as I noticed in the past twice it cannot start when parked facing uphill with less than 1/3 diesel in the stock tank. It's fine when flat/downhill, I keep this tank more than 1/3 full for now and was planning to ask a question when I get home about dropping that tank and looking for possible clogged sock or delamination. Thoughts?
That is a sign the tank sender may have holes in the pick up or it is broken off. Make sure to get an AC Delco TS1012 tank sock. New senders come with gasser socks on them.

Quote:
Originally Posted by CampVan View Post
I did change the stock diesel filter and cleaned out the aux tank, lines and filters last week before starting on my first road trip.
Can you tell if it runs better from the aux tank?
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Old 03-29-2016, 04:19 PM   #10 (permalink)
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Quote:
Originally Posted by CampVan View Post
since I changed the glow plugs and relay last month and replaced the manual momentary hold switch the PO installed ;-)
What glow plugs did you install?

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