Starting Problems - the continuing saga!

[Don Boland]

Since summer is speeding by, I thought I would try to re-open my starting problems. To briefly summarize: I put on Kennedy Exhaust and new injectors several months ago. Since doing so, the truck runs great, but starts like crap unless I unplug the CTS (or ECT for some!) in the cross-over. Since the weather has been has been warmer, initial start has been easier without messing with the unplugging anything, but I want to get this fixed before the cool days come back. Summer is screaming by way to fast!

What is even wierder is that now it seems like there is no pump advance unless I unplug the CTS? Also at times when it is pretty warm (100 or so - yep it happens in Oregon on occasion!), it idle speed goes up around 1000rpm or so, more like it is advanced even though the rig is well warmed up? All of this confuses me, which isn't hard to do.

Like some others, I am about to wire in a toggle switch to disconnect the CTS when starting and then re-connect after a few minutes of run time. But this still seems like I am masking the real problem. Should I have timing checked? (not sure why it started OK with bad injectors and won't now though?). With 190k on it, should I be looking at phasars or a new chain? Is it something more related to bad pump advance for some reason and how would I diagnose?

As always, thanks for any input. This is a great forum!

DB

94' CC Dually 4x4, 6.5td, Kennedy 3.5" exh, FSD cooler mounted on firewall outside of hydroboost - plug down! 189,000 miles. Going for a chip and boost mods (and gauges) next along with fan clutch!

86' Suburban 4x4, 6.2, bad head-gaskets (they're next!), run's great but loses coolant! Wife hates it - I love it! 310,000miles

00' bug TDI, love the mileage and response and the OC's are easy. The rest is a pain to work on. JUST SOLD!

96' Saab 900SE convertible - Fun and easy to work on (sounds unreal for a Saab!).

95 Suburban - 5.7 gasser; The wifes buggy! JUST SOLD with 197,000 trouble free miles - GOT LUCKY?

03' Trailblazer - feels like it has as much ooomph as the wifes old burby - maybe more?

[ucdavis]

Have you tried replacing the CTS? I think I saw it on gmpartsdirect.com for about $13. Cheap & fast R&R if you haven't.
RPMs jumping to 1K doesn't sound like timing change; PCM is changing fuel pulse w/rpms & timing, tho probably not much timing adj. if no load. That could be something else. Solve CTS thing first to see if its bad.

[slagona]

Do you know the history of your injection pump? Your pump is probably working harder now that new injectors are in there with (most likely) higher pop pressures.

I had about 150K on mine (unknown pump history) when I finally installed my new injectors. At the same time, I also had the TDC Offset set to -1.94. Previous to these changes, I had no starting problems, no running problems, ....

It started a little rougher for the few weeks - but now seems to have gone back to where it was before the changes. At first I thought I might be looking at a new pump or having mine bench tested to make sure it still is within specs. But, I'll probably wait til the colder weather gets here to make the final determination. It's running as normal now - last winter I had no starting problems at all.

[Don Boland]

I have had the truck since '96. Got it with about 35k on it, so have done some driving with it. Pump was replaced under warranty at about 74k. It is a green tag pump. Is 115,000 a lot for one of these pumps? Some of the testimony has been all over the board but the updated pumps generally seem to last pretty good.

Thanks,
DB