Intermittent cold start and other newbie questions

[Rik]

Hi everyone, my first post and I hope to better understand my truck.

I've thrown money at a few mechanics and I'm still not fixed. Dealer and private shops. I've read so many forums that I'm thinking this truck is a lemon. I love the truck!

A couple shops said Injectors so those were replaced and no change, then in tank lift pump, fca, fprv, updated #4 injector line, added fuel filtration. Fan clutch Assembly for fun.

I've had this truck for five or six years and it's never changed it's habits.

Cold start in warm weather smokes light color and a miss then clears up fast (10 seconds) and then it's ok the rest of the day.. Parking up hill or down makes no difference. Lift pump pressure makes it to 3psi when start light goes out. With the cat filter it takes 15 seconds approx to work up to 14psi. When I shut off the truck it drops to 0 real fast. I presume that is normal.

What helped the most was the fprv. The truck started great for about a month and again I'm back to a hard start.


My buddy thinks it's a fuel issue with the cat filter from lift pump on start up and wants me to install a fass. He asked me to change to a napa or fleetguard for a test.

So I'm trying to fix this on my own at this point unless someone has a great cummins mechanic in Oklahoma.

Thanks!
Rik

 

[Rik]

Forgot a few things. Sorry.

The oil level does not go up, I've checked blowby with oil cap and that looks fine, had valves adjusted. Fuel rail pressure at idle is 6900, checked wiring at A/C compressor for chaffing, looked ok and has cover over it. Cleaned connector on rail sensor. Aired up tires because I didn't know what else to do. Ha!

Thanks.

 

[p-Bar]

Welcome to TDR . It's sad all thiese parts got thrown at the truck before a proper diagnosis was done. I run a dual filter setup with intank pump that has over 100k on it . I don't monitor the psi so iI can't help you there. What brand injectors were the replacements?

 

[Rik]

Thank for the welcome!

The injectors were from a local shop called Thompson injectors.

Only issue I have is hoping each was the fix only to be bummed out soon after. What is surprising is how many shops shrug the shoulders when I go back. I've got to stop throwing money at it one of these days. I smile and think "hey at least those parts should be good for a while"

Thank you for your response.

 

[p-Bar]

Rik my line is "not all injectors are created equal" . With that the only injectors that should be on that truck are BBI's, New Bosch, Factory rebuilt Bosch. You may have ended up with a bunch of "molested" injectors. Can you get more data from this injector shop what they supplied you?

 

[Bob4x4]

Have you checked for air in the lines while cranking and monitored rail pressure while cranking?

 

[Rik]

Rik my line is "not all injectors are created equal" . With that the only injectors that should be on that truck are BBI's, New Bosch, Factory rebuilt Bosch. You may have ended up with a bunch of "molested" injectors. Can you get more data from this injector shop what they supplied you?

Hi, I'll get the invoice out of the truck tomorrow and see what it says. According to the website they're an approved Bosch rebuilder. For whatever that's worth. Mixed reviews online.

Have you checked for air in the lines while cranking and monitored rail pressure while cranking?

That is the tricky part, I have to wait a while for the edge insight load. That's a key bump and wait. After this wait the rail pressure seems ok. I could be wrong since it displays data in bursts.

How would I check for air? Could I take off my fuel pressure sending unit and poor into a cup? Would that show me?

Thank you!

 

[Bob4x4]

run a clear line to the injection pump,have someone else crank it over normally-no key bump first.you will need a scanner to read the rail pressure while cranking,once it starts will not give you the info you need

 

[cerberusiam]

AFAIK, Thompson doesn't rebuild injectors rather they handle genuine Bosch remans. My guess is you have the standard Bosch reman injectors and you have a bad injector. Cold start in warm weather if you have smoke and a miss, bad injector. Likely the source of the hard start also, probably have one of them bypassing too much fuel.

How and where are you reading LP pressure? You should see 7-9 psi right away then fall off as the LP quits before the WTS goes out. You should not see 14 psi out an in-tank pump unless the install has been botched or the sending unit is flaky. My truck is pushing thru 2 filters and it jumps up to 7-9 as the LP runs, while you have a retro-fit it still should be close to the same.

Did you replace cross over tubes at the same time as the injectors? Failure to do that will cause many issues, almost as many as the reman injectors. Don't kid yourself, Bosch reman injectors are not that great and it is not unusual to have to replace a couple for problems. Regardless of all the recommendations they ARE an issue, main reason why Thompson has replaced 30% of the remans we have bought from them for either outright failure or problems like you describe.

This should have been obvious to whomever did the work along with the long crank problems. Can probably put a scanner on it and find the problem child by looking at the contribution percentages and rpm drop on kill. Doesn't sound like they are helping out much solving the real problem, just changing parts trying to shotgun a solution.