Chevy 6.5 - No start, No CEL or glow plug light
 

Hey guys.. Im trying to get my truck running, ive got a 95 Chevy 6.5TD 2500 4x4

I dont have a security light, so i assume this isnt a security issue.

Engine will crank, i get fuel up to the IP but not after it. Bled the system, i get good flow out of the bleeder but i cant get anything past the IP.

The service engine soon, and glow plug light never come on, so im assuming i have a bad ECM or connection at this point.

Ive checked my fuses, cleaned the ecu grounds and have swapped PMDs to no avail.

Any ideas?

ignition switch? ac delco only

Bumped the ignition switch wires around at the key and got the glow plug light to come on. It flashes sometimes while cranking.

Still no check engine light.. At least im making some progress.. Thanks for the help

x2

Cleaned the ignition contacts.. I just get the glow plug light coming on quickly and going out.still no service engine soon light. Any idea which relay controls the ecu?

I cleaned the ignition contacts and now o get the glow plug light coming on quickly.. Service throttle soon light but still no check engine light or ability to check codes. Any idea which relay powers the.ecu?

The ignition switch is a multi-contact switch that can fail on the ECM contacts but work properly on the starter and radio/blower motor contacts.

There is no relay for the ECM-the ignition switch is still the likely culprit.

A short glow cycle is an indication that the ECM has recently lost power.

I have battery voltage to the fuses but i have just have ground at the glow plug fuse? I'm thinking maybe a dirty ground or an important wire grounding out. one of the glow plug wires was shorted out

Anybody in northern California want to lend a hand? Haha

Another note.. Service throttle soon light comes on 1/3 of the time i turn the key on. I get a flickering water in fuel light as well

No MIL, intermittent WTS lamp. glow plug wire shorted out not good. Now the WIF lamp is flickering.....


MOST LIKELY faulty fuel heater in its death throes... just discussing this Stalling like key was turned off, must be a frigid weather thing...


Anyhow.. Unplug fuel heater at the Fuel Filter Manager. Check all your fuses again, specifically those in the underhood fuse/relay center. ENG 1 & 2, ECM A & B, one of those protects the GPR and LPR circuits.. replace as necessary.
Turn the ignition ON, wait 20 seconds to give PCM the time to initiate the start up mode, cycle the glow plugs, then turn the ignition OFF. Repeat again, this cycles the PCM and hopefully resets it back to its normal mode. Then try starting it like normal again. See if this restores glow plug operation and start up.. If not, perform "GP System Check."
Note the location of the fuel heater in the GP System Schematic, then note the location of the 10 amp Gauges fuse in the NO MIL schematic.. Also worth noting in the MIL schematic, the fuel pump's, fuel pump relay's and PCMs (PC1) System Ground "connections". When the fuel heater malfunctions, shorts out internally or externally, it can send 12volts back through the common shared/spliced/group'd ground(s) and cause system wide havoc..


Now about that NO MIL (Service Engine Soon) and annoying STS lamp.. it could all be related..

Thank you so much for the reply. I realized i get the glow plug light if i have the batteries fully charged.. havent had enough time to see if the glow light is acting up still.

I got the truck for free from a friend and they said it turned off like the key was turned and would crank and not restart.

It also had an alarm that i removed. I was unable to find any cut wires to disable it from starting... i checked under the dash and by the ecu.. its just another thing to add to the mix.

Thank you so much. Im trying to get the truck running ASAP so ill be updating this thread often.


Whats the average real world MPG on these trucks in proper running order?

I ave 18ish... lil more interstate, lil less in town..
20mpg isnt unheard of either...

Hey can someone help me on my truck , I have a thread already but no one has replied yet ,, need help from one who really knows what they are doing and this 95 6.5 td truck:s:

Try reconnecting the alarm or look into a alarm system just like to , look in the instructions it should tell you how it's wired and what exactly it's wired and tied into , it sounds like the alarm system is tied into the ecm or pmd power or could just be a burnt out pmd iv noticed that gm made these truck very complicated and poorly designed , and ran circuits in pair with other circuits. So even tho you may not see anything cut worth it being vital to the truck running or not , you'd be surprised .

So I got around to putting a little time in on the truck..


As a recap..

The glow plug circuit is my main concern. As previously stated the glow plug circuit has negative 12.5 volts, so something is up. The ecu wont power up and the dash lights sometimes come on and dont.. it will crank but not start. The truck had an alarm that i removed when it wouldnt start, 2 relays and a fuse were removed, no wires were cut on the alarm install so im keeping it in mind that the relays could very well have controlled something. Ill ask the ex owner (friend) if the alarm was wired to control the engine.. They said it turned off like the key was turned.


Recently I disconnected the 2 wire 3 prong connector by the filter housing, pretty sure this was the fuel heater, i need to verify. I also unplugged the glow plug controller and i still got the same reading of -12.5 volts on the circuit that is supposed to be positive (im pretty positive.

Ill check to make sure i disconnected the right plug for the fuel heater, but im becoming clueless why i would get negative on the glow plug circuit even if it was the alarm cutting it off, unless it has something to do with the crazy electrical system these trucks have.


Thank you guys! Im itching to have this thing running!

PS. The alarm would take some work to hook back up, but if this looks like a possibility, let me know

batteries connected backwards or charged backwards?
leads reversed on the multi meter?

The batteries are charged correctly and the other circuits test out normally so im pretty sure something is grounded out.

Ill verify that i do in fact have the fuel heater unplugged then disconnect anything on that circuit and see if anything changes. Any other ideas?

I have pretty much the same problem you'll be driving an it'll randomally stall like you shut the key off when an when you go to restart it I noticed the service throttle soon light would not light up an the glow plug light wouldn't light but if i let it sit for a few hours it'll sometimes start an run normal if it's not hot out but on a hot 80° degree day won't start at all I've replaced the PMD remounted it behind the bumper replaced the ECM replaced the ignition replaced the glow plug controller an im at a loss im so ready to scrap the damn thing it's a money pit an I still can't figure it out :/ mines a 94 k2500

To everyone except OP (original poster aka schmauster) needing help. Please start your own threads so theres NO CONFUSION. Someone will be along to help you shortly, if they can..


Engine just shuts off as if a ghost had switched the ignition OFF..

Start with the Important Preliminary Checks, followed by OBD System Check for any DTC(s), followed by a lengthy series of monotonous Fuel Supply System Checks.

ANYTHING that disrupts the Optical Sensors relaxing day at the diesel spa will alert the PCM. If the PCM remotely feels threatened or remotely suspects catastrphic damage is imminent, the PCM shuts EVERYTHING down just as if a ghost turned off the ignition.. When the PCM hits the panic button, entire system shuts down and appears dead because nothings communicating. PCM's posum play can last as long as 20 seconds while it reboots and gathers its senses. If the condition still exist when the PCM reboots, it can immediately default and/or just hit the panic button again and again or until the condition no longer exist. Grind the starter (crank the engine) all you like, dont matter. Engine will not start until the PCM says so. Often this condition is ROUTINELY misdiagnosed as faulty IP, defective PCM or failing PMD.

Dont skip the "Important Preliminary Checks" and dont simply go through the motions, be excruciatingly THOROUGH!!

Dont forget to check the last ditch screen..


Air is the EFI 6.5TD Kryptonite.
Grungy Grounds, its Nemesis..




Ive attached a pic of the FFM. Should help you to identify the Fuel Heater which has 2 wires whereas the WIF sensor has 3.

The fuel heater's element are known to short out internally.

Had to hunt for your thread, found it in the tech review.?.? Maybe a mod can move it to the appropriate forum... Until then, heres a link.
No Glow Plug, No Start

I will just say thaT I have had to replace the ignition switches in all of my vehicles except the 1994's I've had.

I got to the point where if the problem somewhat indicated the ignition switch and there was 200,000 or so miles on the vehicle I would just change the ignition switch - with a GM or AC Delco.

I did do a fair amount of diagnostics to rule out the usual suspects before changing the switch.

Every time I changed the ignition switch, it cured my problem. I've changed 5 ignition switches. All at around 200,000 miles.

I would say age and miles driven at the hit of the key would have more to do with things than the actual miles on the vehicle

Depending on where you are checking the glow plug system, things will go to ground. If you check a glow plug wire and any of the glow plugs are plugged in the wire will show it is grounded.

Glow plugs are grounded and all the wire get tied together at the controller

I've been at a standstill for a while due to money but hopefully soon I'll get some new batteries and clean my 3 passenger side ecu and any other grounds I can find with brake cleaner, a wire brush and electrical contact goop. A new acdelco ignition too.

I've been doing a lot of reading on here along with the helpful posts in this thread.

Knowing that the ecu will power down at the first sign of trouble is really helpful. Thanks guys, I'm tired of my nice and first diesel truck just being a lawn ornament!