Engine/Transmission (1998.5 - 2002) VP44 Injection Pump/Connector Wiring...

[jcbrown]

[Excuse the poor quality of the digital photos]



Upon removal and inspection of the VP44 injection pump/connector wiring, I noticed crease marks in the wiring insulation. I removed the boot and cable tie from the VP44 connector and rewrapped the wiring to eliminate this wear spot.



Remove two screws, connector cover, and cable tie to access the wiring:



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Rewrap with friction tape and install new cable tie:



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I believe the edge of the factory wire loom was rubbing the wiring insulation.

 

[John - K5AWO]

Good find jcbrown. Wonder how many pumps were disabled by just such a condition?

 

[MCummings]

I just took that adaptor apart earlier today trying to chase down a P1689 (No communication between inj. pump and ECM), and found the same thing, except my wires werent creased. There was a green wire (Adjacent from the empty slot) that had it's actual wires exposed.



I'm still hunting down my no Comm. problem though. .



Merrick

 

[JR2]

I am going to bump this to the top... so I will remember to go look at mine tomorrow.



Good Catch.

 

[dsather]

1689

Merrick



I've had my truck throw this code twice. Both times when i was started. The engine would rev up like I had my foot no the throttle. After the first time I unplugged the connector to the ECM and to the VP. Cleaned them up and reinstalled. I also removed the scotck lock on my pump wire and soldered it. A week later it threw the same code in the same manner again. I cleared the code and have about 2500 miles on the truck with no code.



If you track down this 1689 code problem on your truck I would LOVE to hear about it!!!!



I don't want to buy a new pump if I don't have to especially if the pump is not the problem. The truck runs really well.



Dennis

 

[MCummings]

The problem I was having when I got the code is the truck has no power (Acting like a bad MAP sensor), and lopes alot when over 8MPH, and at idle, to the point of shutting off (450-1,200RPM).



Now,, I don't have a code, but the truck is behaving exactly the same... .



This code is kickin' my butt, so it's at a more experianced shop and the are worming their way through the wiring harnesses as we speak.



Merrick

 

[Mad Bomber]

Pump

Dsather, I had that happen to my truck also. I had a bad comp box and I also grounded the comp to the battery. Since doing both things no more problems.

 

[Beast2B]

Dsather, Possibly the APPS is acting up. Have you tried the re-calibration?

 

[dsather]

It will be interesting to see what Merrick's problem turns out to be!



Of course the box would be one of the things you could suspect. One of the times my truck threw the code, the box was off. The other time, I'm not sure.



The apps has been calibrated a couple of times. Never had a problem with it that I know of. The codes thrown point to the no communication issue. It started up like my foot was on the throttle running rough but settled down within a second and acted completely normal from that point on but with the check engine light on. By the way, when I removed the scotch lock and stripped insulation back to solder my pump wire I found a couple of broken wire strands from the scotch lock. I don't like those things for something this critical.



I did not unravel the harness to see if there was an insulation problem. I'll be doing that soon.



Dennis

 

[2-ND TIME]

engine problerms

No or low power sounds like no cct through the on and off - idle validation ccts on the pins maybe 1, 6 and 1 ,2 as on mine that is why one has no more power on acceleration from stand still .

 

[Beast2B]

Shouldn't you set another code for the APPS if it's not sending voltage within parameters? I would think that an open circuit should set some code... ?

 

[KevinK]

My truck started having the same problem (1689) about three weeks ago. It has been throwing the 236/237 (MAP sensor) codes for about six months, but it didn't really affect drivability. The no power problem comes and goes at random times, with or without the COMP turned on. I disconnected the data-link last night to see if that makes any difference.



Kevin

 

[2-ND TIME]

engine problerms

Please Please

Check the pins 1&6, and 1&2 for continuity should be less than 125 ohms this could be the low power problem that many are seeing or not reconizing this off- idle to me will give one FLAT POWER acceleration! If the ECM doesn't see the throttle advancement that it should you won't get more power (yes -no)

For mine in 2nd gear rev it up to 2600 no boost ,shift 3rd gear about 5 lbs boost, small acceleration. Again have measured 4 new APPS and they are bad out of the box. Not ,bad engineering bad, quality control!. Gutless Bloody Wonder. :-{} :-{} If anyone can measure their APPS resistances if would be of Grrrrrrreat help to me. Thanks

 

[Gary - K7GLD]

With a digital VOM, I show zero - or infinity resistance to 1&2 or 1&6 on 3 different APPS units -



With an analog VOM, 1 APPS showed 24K, the other 2 showed 6K. Rotating the throttle shaft makes no change in readings...



I don't always trust digital meters im measurements like this...



here's a printout of pin functions:



the connections to the ECM from the APPS:





APPS ECM

---- ---

1 >--------BK/LB--------< 11 (B+)

2 >--------LG/DB--------< 16 (Idle Val. Switch 2)

6 >--------BR/OR--------< 1 (Idle Val. Switch 1)

4 >--------BK/YL--------< 32 (APPS Sensor Ground)

3 >--------LB/BK--------< 25 (APPS Sensor Signal)

5 >--------DB/WT--------< 31 (APPS Sensor Supply)

 

[John - K5AWO]

ummm... . Gary, you might want to EDIT that post.



Zero resistance is like less than 0. 0000001 ohm or a dead short.



Infinity, which is what I think you mean, is an OPEN or no continuity at all. ie, greater than many megOhms or the resistance of air. In your country, that might be measurable ) but over here in Phoenix, the parchment paper is crackling up and blowing away.....



Tnx for the info on the connections. One more page for my book that is getting thicker.

 

[Gary - K7GLD]

AHHhh - terminology - yer right - an open, infinite resistance - that's why I used both terms - to make it clear (or maybe REALLY confuse ya!)



But in any case, the analog meter got it right



I *am* sorta curious as to the large difference between two of the APPS and the other - is one bad and the other 2 good - or vice-versa - or is the precise value not that critical?

 

[John - K5AWO]

I suspicion your test subject APPS may have been used with two different variants of the VP44 pumps. In any event, the total resistance end-to-end of the range is probably not significant (WAG here), rather IMO it is the percentage of the variable arm as to its' current position at any given time.



Example: Two different potentiometers (APPS, whatever) have 6k ohms on one and 24k ohms on the 2nd. 50%, or half throttle will still give 50% voltage at 3k mid-range on the 1st and 12k mid-range on the second unit.



Never having opened a VP44 or having one to play with (any donors out there? for a test unit??) I have no way of knowing if they are measuring actual voltage, or using the variable resistance (wheatstone bridge configeration?) to change the timing of an oscillator and measuring the frequency (easiest to do in a digital world).



Has anyone ever used an oscilloscope to monitor for any possible wave forms on the APPS units? Would be nice if the factory manuals would get that detailed. (don't want to release a trade secret, I am sure)

 

[John - K5AWO]

Re: engine problerms

Originally posted by 2-ND TIME

Please Please

Check the pins 1&6, and 1&2 for continuity

2-nd Time;

Normally I would do that in a heart beat... but, my Dodge is the only piece of reliable transportation I got right now and I can't afford the off-chance I would do a dumb $%^@ mistake while probing around with the meter/scope leads.

Those four in the box, you took them back for replacements?



John

 

[Gary - K7GLD]

One of our group is working at tracing out a schematic from a donor APPS I sent him - that will be a big help in trying to figure out the innards of the units - check the thread "anatomy of an APPS" to get some idea as to how they are made and what's inside...

 

[KevinK]

I got a strange result when I completely disconnected the COMP. I ended up with a hard failure and the SES light on. I don't have a code reader, but it was exibiting the same "no power" symptoms associated with code 1689. I reinstalled the comp box and it instantly started running fine again (SES light is off). I love these electrical probelms.



Kevin