I need some assistance here. Let me give you the run down of what I have going on..

Recently built up a 22re with lcengineerings's headers & downey intake, and the "Engnbldr 261 Cam . This is for a pickup with an AUTOMATIC transmission.


Issue #1: Timing:

The book says 5degrees btdc with check connector plugged.

We do this, and the truck idles nice, HOWEVER if we press the brake rpm is not steady and jumps up and down continuously. We checked for vac leaks. Could not find any.

We currently have it set at 5 degres btdc without the connector plugged and it runs _ok_.

Issue #2: Idle.

we have to idle around 1100rpm otherwise when we put the tranny in gear it stalls. Shouldn't the truck compensate?

Do you have suggestions?

Issue #3: TPS

Do you have suggestions on how to correctly set this? So we can verify our configuration

MAF has not been adjusted yet, as we do not believe it will help our idle issue.

Your sugestions regarding "MAF, "TPS", "IDLE", and "TIMING" would greatly be appreciated.

>>>*BUMP!!! *How about some of you sharp folks giving this gentleman some tips on this one?

It has me puzzled a little, it almost sounds like a vaccum leak but perhaps the header/cam combo is killing backpressure?

That shouldn't happen with the 261C but maybe, if the head has been resurfaced and the cam is then timed late?....*EB

Make sure the TPS is adjusted right first:
- http://www.4crawler.com/4x4/CheapTricks/TPS/index.shtml

Then set the timing, then turn down the idle speed:
- http://www.4crawler.com/4x4/TLCA_TruckTech/TruckTech.04.09.html

And there is probably some sort of idle/throttle kickup device for the A/T, make sure that is working OK.

1. Timing is right. Make sure it is set at 750 rpm, or the reading will be off.

2. The higher idle is the cause of the cyclic rpm when the brake is applied. Leave the idle where it is when setting the timing.... It will bump up some when the jumper is disconnected.

3. Follow the steps in 4crawler's link for TPS setup. I don't think this is the cause, since the timing settings work out when shorting the check connector. Find out how the auto bumps up the idle when in gear, and look there. Something is sticking, and now allowing the idle to come up when in gear.

engnbldr,

It is one of your heads. If it was resurfaced it was resurfaced before I received it.

I will look at the other suggestions. As far as i know, there is nothing that mechanically bumps up the idle with the auto transmission unless its vac related.

I also hear a lot of mixed reports, on the 261 and its idle speed. Many people state it will not idle at 750...



Backpressure.. It should be decent on backpressure. Its got a cat and a muffler on 2 & 1/4 pipe so I do not think its losing much backpressure considering, my friend had 2 1/2 pipe to a flowmaster (no cat) before rebuilding.

You've got to adjust the TPS before you adjust timing or it won't be right.

>>>*That is just part of the manfacturing process, they are all surfaced even brand new, they can't cast them to flatness....*EB

x10

The fluctuating idle is definitely caused by too high of an idle but if your truck is running bad it will idle fine one day then high enough the next to cause the fluctuations.

If you want to eliminate the problem completely there is a lead you can cut that sends a brake signal to the ECM but I'm not entirely sure though that I would cut it if I had an auto transmission as that is the situation it is designed for supposedly. And this is a band aid for another problem at best.

However I dealt with the idle problem for 12 years and was more than happy to cut the wire. It fixed the problem completely.