Engine/Transmission (1998.5 - 2002) Cranking hard, Hard Start when Hot, had P0121 DTC, but no codes now.

[KrisKringle]

Hello all, it has been a while. Greetings from Germany

A few weeks ago, I was pulling out of the Garage, and experienced a short episode of the dreaded "Dead Pedal". CEL came on , but suddenly the truck ran fine. Cycled the key three times, the CEL went out Read the codes, and saw the P1692, and then wiht the scanner, read and cleared the P0121 codes. Since the last inspection (TÜV- 3x they run the engine at full throttle for 10 seconds to measure emissions), the truck has been displaying the following symptoms:

1. When starting the first time when the engine is cool, it sounds link the timing is too advanced, i.e., the Starter sounds more under load than norma / cranks slower. Previously, I just needed to bump the starter, and the engine would fire right up. (Both Batteries were replaced a year ago).

2 When hot, I have to crank the engine (ten seconds) or more untiul it starts. When it starts there is a puff of black smoke.

I am planning to clean the IAT (still have not got around to it) and put in a new MAP Sensor.

VP44 was changed by the PO around 40K ago.

More info, while on the scanner I checked the values on the TPS; 00% at idle (not running), 100% on the floor. Pressing the pedal gave steady readings through the scale, not skips, hanging or otherwise.

The truck has over 280 km. Stock engine, put in the Boch 275 injectors around 20K ago. In case it is not in my sig, the truck is a 2001 25000 5 speed. Thanks for your help....

 

[JR]

Did the code come back after you reset it?

Sounds like it is OK according to the reported values on the scanner but is very possible to have an intermittent issue.

What are your batteries voltage prior to starting when cold? You could either have a slow draw causing a low battery, other possibilities could be loose/corroded terminals or grounds or a starter on its way out.

MAP and IAT sensors shouldn't have an affect on the hard start when hot but it never hurts to clean them. Probably a little premature to replace the MAP sensor unless you've got some other symptoms/ codes you didn't mention.

 

[KrisKringle]

Did the code come back after you reset it?

Sounds like it is OK according to the reported values on the scanner but is very possible to have an intermittent issue.

What are your batteries voltage prior to starting when cold? You could either have a slow draw causing a low battery, other possibilities could be loose/corroded terminals or grounds or a starter on its way out.

MAP and IAT sensors shouldn't have an affect on the hard start when hot but it never hurts to clean them. Probably a little premature to replace the MAP sensor unless you've got some other symptoms/ codes you didn't mention.

Thanks JR,

Battery terminals are in order. It could be the starter is on its way out, perhaps it no longer has the ,umph' to spin the motor with enough gusto as before. It sounds like the batteries are weak, however the spin rate does not fall off as it would if the batteries or terminals were not in order.

Codes have not come back. When reading the MAP sensor values with the scanner, the value with the engine off was 192 KPa, (0.05965 Hg) with it running at 2000 rpm, only went to 202 KPa. I am wondering if it is sending a signal to the ECM, and the VP44 is advancing the timing. It sure sounds like an engine with too much initial timing.

 

[JR]

It's been a long time since I had a truck on a live scanner but I don't think your numbers are too far off in relation to each other. Keep in mind revving the engine in neutral there is no load on the engine. No load = very little boost.

Aside from checking voltage after the batteries have been sitting you could also have an auto parts store perform a load test on the batteries. They should do it for free.

 

[KrisKringle]

Maybe Starter, but...

It's been a long time since I had a truck on a live scanner but I don't think your numbers are too far off in relation to each other. Keep in mind revving the engine in neutral there is no load on the engine. No load = very little boost.

Aside from checking voltage after the batteries have been sitting you could also have an auto parts store perform a load test on the batteries. They should do it for free.

The truck hardly ever sits...in fact, we just came back from a 2.700 km trip through Germany, Austria and Italy pulling a 25' Camper. Through the Alps as well, and it never missed a beat. I use the truck every day for my work here as a Carpenter.

Here is a picture with over 1.2 metric tonnes on the truck (2.600 pounds) and over 3,5 metric tonnes (7.716 pounds) on the trailer.

https://www.dropbox.com/s/za84y4ohrz55zhd/SAM_2428.JPG?dl=0

As far as a load test, I can do one at the shop a friend of mine owns here http://melchert-automobil.de. However, measuring the voltage just now (12,6 V), and cranking / starting 3 times, the voltage was 12.4 v. I think maybe it is time to change the starter, as it appears to be the original. I was thinking that the MAP sensor was telling the ECM to advance the timing due to a false signal. I have all of the important sensors here in stock; Crank, Cam, MAP IAT, and APPS. I do not have VP44 yet. (I am thinking about one of the Blue Chip Diesel 2.400$ pieces, but...) I am over in the States, and I will bring back a new PS pump and lines. The starter is available over here, and the price is not too much different.

More infos: at 2000 rpm, the scanner was showing a 2,2 % load...

BUT! I am not one to just start bolting parts on. Where is Joe Donnely or Marco?

 

[JR]

The MAP sensor does not advance timing. In fact you can comoletely unplug the sensor and the truck will still start. The VP does not look at any of these sensors when starting, it simply needs 12 volts to put it into open loop and it will start and idle.

First thing first correct the slow cranking. The VP is essentially a mechanical pump with electronic timing. When the pressure created during cranking is not enough to pop off the injectors, the engine will not start. The other possibility is the distributor in the injection pump. When the distributor is worn out it takes longer to build pressure when hot due to thermal expansion.

Blue Chip has a great write up on diagnosing hard starts when hot, I'd follow his trouble shooting.

http://www.bluechipdiesel.com/vp44_diagnostics.html

 

[KrisKringle]

looks like the starter is the culprit.

The MAP sensor does not advance timing. In fact you can comoletely unplug the sensor and the truck will still start. The VP does not look at any of these sensors when starting, it simply needs 12 volts to put it into open loop and it will start and idle.

First thing first correct the slow cranking. The VP is essentially a mechanical pump with electronic timing. When the pressure created during cranking is not enough to pop off the injectors, the engine will not start. The other possibility is the distributor in the injection pump. When the distributor is worn out it takes longer to build pressure when hot due to thermal expansion.

Blue Chip has a great write up on diagnosing hard starts when hot, I'd follow his trouble shooting.

http://www.bluechipdiesel.com/vp44_diagnostics.html

Thanks, I have seen, and read through the whole thing. I was having palpitations that I would suddenly need to shell out 2.400$ for a pump. the diagnosis seemed to rule that out. You would not happen to have the PN for the starter handy, would you? I was thinking of swapping it out prophylactically before our trip given the miles on the truck. Given that ere are no codes, it is looking like the starter is on its way out...

 

[JR]

Sorry, I do not have any part numbers available. I went the route of rebuilding mine, not that it needed it (yet) but I tend to do these type of things before they need it. A good rebuild kit from Larry B would be much better alternative to a chincy reman starter and is cheaper to boot. The only better choice would be a NEW unit, which would be quite costly and not really necessary.

http://www.fostertruck.com/cummins-dodge-denso-starter-easy-rebuild-kit-94-06.html

 

[KrisKringle]

Part number is Dodge 5016522AA...just ordered one for 175€. given the weight to put it in my luggage would probably end up costing another 100 USD. Ordering it from the US would cost about the same with shipping and taxes. I will install it next Saturday, and post the results. However, given that there are no codes present, the batteries are in order, and the truck has over 280K km (175K miles), the best bet is the starter is going south...Oh, and I spoke with my Brother (mrhemi, I think) and he told me his '96 started doing the same thing at only 75K miles...Remember, I am in Germany. Since Fiat took over Chrysler, parts houses have been closed, and many of the parts have been ,obsoleted.'

 

[KrisKringle]

Sorry, I do not have any part numbers available. I went the route of rebuilding mine, not that it needed it (yet) but I tend to do these type of things before they need it. A good rebuild kit from Larry B would be much better alternative to a chincy reman starter and is cheaper to boot. The only better choice would be a NEW unit, which would be quite costly and not really necessary.

http://www.fostertruck.com/cummins-dodge-denso-starter-easy-rebuild-kit-94-06.html

I have the improved contact set here. When the new starter arrives, I will put in the improved contacts before it is installed. Thanks for you comments and support.

 

[JR]

Still unsure over the long crank time when hot...unless the starter is lugging all the time I would think the problem lies elsewhere on that particular problem. You indicated in your first post the long start times are only when hot, usually IP related but the batteries/starting system must be gone through and dismissed first.

The solenoid and brushes are essentially the only wear items in the starter, if you've already got em I'd put em in and skip the new starter (just personal preference)

Good luck and please keep us updated.

 

[KrisKringle]

Not the batteries then...

Well, here is an update. Due to short arms, and a lack of longer leads on the Voltmeter, I had someone measure the voltage at the battery while cranking. (First I checked the batteries when isolated-12,6V on the right, 12,62 on the left) The right side had 9,9V when cranking, the left 8,9V. The lower voltage could be due to the fact that the measurement was taken on the second round of cranking. The batteries are 3,5 years old. Put in two new ones. Result? No change. I will put the new starter in today...Alternator also checked, BTW. 13,8V, at the alternator, although a bit over 14 is indicated on the dash. Brushes are a bit on the short side, so I ordered a rebuild kit from Geno's.

 

[KrisKringle]

Changed the starter. Thing starts like a champ again. Took the old starter apart, and there was a mass of old grease, black chunks of what I do not know, black dust and gunk inside. Commuter does no look burned, but the brushes are only about a 1/4" long...

 

[JR]

Good to hear!