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fish biting?

Fuel rate at WARM idle with no accessories going (no DRL's, no radio, nothing) should be close to 10 mm^3 on a good IP...
 
well, schiker, truck has 178000 miles. i bought it about 4 months ago, so i have no idea if IP has been changed, or if any engine components have been serviced. i plan to replace injectors, and glow plugs in the future, but i have to take things slow. budget is limited. if IP has to be replaced i want to be very deliberate about my troubleshooting so i KNOW the IP has to be replaced. again, thanks!
 
well, now i have checked the FSO solenoid, the IP fuel inlet screens, and the return checkvalve. all are clean, and seem to be functioning properly. any other suggestions?
 
I had a simular issue as well. I replaced the same items only mine is a 99. Called Heath and got a new PMD (FSD) injectors, glow plugs, GLE4, coolant upgrade and a LP. Plus I dropped the tank and made new ground cables and cleaned everything. sputtering still exsisted. I end up pulling out the optic sensor from the IP, and cleaned it with alcohol. Based on some of the other guys cleaning there optic sensors. Well,.... it end up fixing the sputtering and has been running smooth and sputter free for the past month. Now another thing to look at is the weather pack connector that plugs into the optic sensor outside the IP and see if there is signs of diesel leakage at the plug coming from the IP through the connector. This might cause mixed signals if the pins are soaked in diesel.
 
thank you G, it seems that all that i do leads me to either the IP failing, or the electronics on it. cleaning the optic sensor is about $440 dollars cheaper than a reman pump!
 
For a quick and dirty IP test, do this. With the engine at operating temp, and in neutral, try to run the engine smoothly up to 2000 rpm, hold it there, then slowly ramp it down to idle. If you can't do it smoothly, you're probably on the last legs with the IP. Any hot start problems?

I agree clean the optic sensor first. You've been very thorough on chasing electric problems, lets see if that solves it.
 
X2

I was getting discouraged with my truck and thought gees I could have put a gasser in and be done. But I knew I would have shot myself in the pecker in the long run as I tow alot. I hate little problems and It drives me crazy if I hear a noise that isn't suppose to be there or an exhaust leak and especially if I don't know what is causing the problem. I don't rest til I have it fixed, I guess it is a curse of mine. So all my vehicles have to run like a sewing machine or else. I am definetly happy with my 6.5 with performance and economy. Just hang in there and you will gain more than you would imagine otherwise.
 
thanks guys! i do like my 6.5, and i too am a perfectionist. i do have the beginnings of a crossover exhaust leak, and yes, it is driving me nuts. as far as the IP, the more i do, the more it is pointing to IP electronics, and IP replacement. I will clean the OS, and pray for a few more miles, but in the end, i know what is going to happen. you can't beat the milage of a 6.5, and i think i have more power with my 6.5 in my 96, than i did with 350 vortec in the 98 i had. when it runs, it runs GREAT, when it doesn't, well, it drives me crazy! as i am on a budget, i will try cleaning OS first, if that doesn't work...well, you know what will happen! appreciate all the help, and i'll keep you all posted!
 
Check to see if your IP has a filter harness on the optic sensor... this is NOT the same one as runs to the PMD.

It looks like this:
106394_3.jpg


If it does, take the filter harness out and re-connect the wires - they just plug right inline.

If that solves your problem, then you probably don;t need to buy a new one - the OBD-II systems were supposed to have that filter built into the PCM - and can just run without one.

Intermittent “FISHBITE” type misfire or chuggle in the 1994-1995 GM 6.5
This refers to the occasional, isolated miss that occurs at medium to heavy throttle in the GM 6.5.

Most commonly, this is caused by a failure of the “Electronic Filter Harness”. The failure of this harness can set DTC’s 17 & 18. This harness is about 8” long with a male connector at one end with a female connector at the other. Located in the mid section of this harness is a molded rubber section, which contains the resistors.

The filter harness plugs into the rear of the optic sensor on top of the fuel injection pump (top rear). It connects between the optic sensor and the main engine harness under the intake manifold.

It can be changed out without removing the intake manifold, using a screwdriver to release the connector latch. With the latch released, push the connector toward the rear of the engine to disconnect. Then pull the connector and harness up out of the valley below the intake manifold so that you can reach the connector at the opposite end of the harness. This connector too has a latch that must be released before the connector can be disconnected.

Simply reverse the procedure to install the new, updated GM Electronic Filter Harness (Part #HDP1404). The filter harness can be checked for resistance, however we do not take chances with them. We replace the harness anytime we find one that is original.

If you have questions about these comments or about any of these products or any other Heath Diesel product, please feel free to contact us. Toll Free Phone 1 877 894 6266 or email [email protected]

- Bill Heath

Related Links:
GM Electronic Filter Harness for 1994-1997 6.5 (Part #HDP1404)
GM 6.5 Diesel Parts
 
I have to agree with everyone that is pointing at the Optic Sensor. I had codes 0251 and 0370 and it was fuel related. I was using a bad veggie blend and I think it clouded the optic until I ran some BIO through it.
 
well, i took the pickup on a small trip last night. what i figured out, is that it is worse after it has warmed up, sits for awhile, and then run again. my best guess iss that when warmed up, and shut down, the OS has a chance to heat soak. when fired again, chugs, and farts. it only gets worse on the way home. so, i am thinking that the OS is toast.

i was also going to ask about the OS filter harness. I have a 96, i had heard that the filter had been built into the ECM, am i correct, or do i need to get another harness? this problem has been happening even before i took the filter out. any info would be insightful.
 
no, no hard starts, always cracks right off. no veggie, no bio, straight petroleum fuel, with stanadyne additive.

Most of us add 1oz of 2-stroke, or SAE 30 non-detergetn (no dark dye) per gallon of fuel, 1:128 ratio, it helps lube the IP due to the new Ultra low sulfer diesel. Its alot 'dry'er then the LSD that was out when our trucks were designed.

Give it try, i've read stories where it's made peoples codes go away, .

At worst, your injection system will be getting its required lubricity.
 
i'll try the two stroke oil, though i was SUPER impressed with the stanadyne additive. i was setting codes as fast as i could clear them before the additive, but after i added it, codes went away, but hiccups and farts stayed....until now anyway. price between additive and two-cycle are about the same here, but it is worth a try. thank you!
 
Matt how does the 2-stroke oil compare to running QMI Fuel treatment. I know the QMI does more only needing 6 oz per tank but I would think lubrication is more of an issue than water in the fuel.
 
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