Troutmobile on the table

chitwnvw · Post by **chitwnvw** » Mon Mar 23, 2009 12:24 pm

Man, I don't want to be welding anything.

chitwnvw · Post by **chitwnvw** » Mon Mar 23, 2009 12:25 pm

dingo wrote:i always start with compression test and go from there....i might have missed where you mention that

Mark took one beforehand. That's why I replaced 1 and 2 head with a rebuilt one. Machinist did a vacuum check.

deschutestrout · Post by **deschutestrout** » Wed Mar 25, 2009 7:09 pm

Okay. I got home and looked at the bus to see if I could see anything obvious. Replaced several of the small diameter vac lines that were cracked. Replaced the lil rubber "L" boot in the middle of the engine compartment connected to the ? and ?. Still no go. Starts up quicker than it did before Chi replaced the head...but will not stay running. Occasionally backfires when I nurse the throttle to try to keep it running. What other variables are involved when a head is replaced? Prior to Todd's arrival, I started it, it idled...it would run unattended so I could let the engine warm up to do a compression test. Now, starts quicker but immediately stalls.

vdubyah73 · Post by **vdubyah73** » Wed Mar 25, 2009 7:43 pm

If it starts and stalls within a few seconds it is usually either a vacuum leak or the double relay is not switching over to the run side. The reason it will start and stall right out with a vacuum leak is the cold start valve is richening up the mixture enough to compensate for the vacuum leak. It squirts for about 10 seconds. The double relay can be hotwired but first give it a couple sharp raps with a srewdriver handle, they can and do stick internally.
here is a link to ratwells limping home with FI.

http://www.ratwell.com/technical/LimpingHome.html

here is a link to double relay info. Colin has one here somewhere too.

http://www.ratwell.com/technical/DoubleRelay.html

double, triple check valve adjustment. Make sure cylinder tin isn't interfering with manifold to head seal. Double check firing order. All on the side the head was replaced. Worst case is the head needs to be retorqued. If you pop the valve cover and remove the rocker ass'y, paying attention to details so you can replace it properly, you can check the torque on the lower head nuts. If they are only slightly lose, tighten and reassemble. See what happens, quite often that will fix it. For whatever reason the lowers will be lose and the uppers will be OK.

tristessa · Post by **tristessa** » Wed Mar 25, 2009 7:44 pm

Head temp sensor connected? Grounds bumped loose under the plenum? Vacuum leak at the intake ports, fuel injectors, runner-to-plenum sleeves? Cracked S-boot? Snug connections on the S-boot?

.. AFM plugged into the harness?

IFBwax · Post by **IFBwax** » Wed Mar 25, 2009 7:49 pm

Brake booster nice and snug even if it looks like it from above?

deschutestrout · Post by **deschutestrout** » Wed Mar 25, 2009 7:58 pm

One thing weird is that the PO (or his mechanic) had tapped a hole in the tin and moved Temp sensor II from #3 to #2. Chi moved this back to #3...and now it won't stay running. Coincidence or cause? Is there already a threaded hole in the head he put in to accept the sensor? I dunno..didn't see the head until after it was installed. From what I understood from a previous thread I started, head is a head and has a threaded hole no matter which side of the bus it's installed on.

IFBwax · Post by **IFBwax** » Wed Mar 25, 2009 9:09 pm

deschutestrout wrote:One thing weird is that the PO (or his mechanic) had tapped a hole in the tin and moved Temp sensor II from #3 to #2. Chi moved this back to #3...and now it won't stay running. Coincidence or cause? Is there already a threaded hole in the head he put in to accept the sensor? I dunno..didn't see the head until after it was installed. From what I understood from a previous thread I started, head is a head and has a threaded hole no matter which side of the bus it's installed on.

Yeah I was thinking that too. Why move it? Maybe something was wrong with the hole in #3? Can you move it back to #2 and see what happens?

chitwnvw · Post by **chitwnvw** » Wed Mar 25, 2009 10:08 pm

Is there a way to tell which of the electrical connector, the ones that connect to the intake runners, which one connects to which cylinder? I put a peace of tape on the number 1 cylinder but the tape fell off.

I swapped these connections but that made no difference.

LiveonJG · Post by **LiveonJG** » Wed Mar 25, 2009 10:14 pm

OK, deja frikken' vu here. Remember when I said that replacing the wiring harness solved my similar trouble? The problem with my old harness was that someone had bypassed the original Temp II connection and run a replacement from the pin in the control plug to the Temp II. So, how is your Temp II connected? Because the original wiring couldn't possibly reach No. 2. How has it been hacked?

Then again, going back to 2 with the sensor seems a good place to start.

Mark, you are correct, a head is a head and the tapped hole is either going to be on 3 or 2.

-John

tristessa · Post by **tristessa** » Wed Mar 25, 2009 10:14 pm

chitwnvw wrote:Is there a way to tell which of the electrical connector, the ones that connect to the intake runners, which one connects to which cylinder?
I swapped these connections but that made no difference.

It doesn't matter which one goes where, and swapping the connections shouldn't make a difference. L-Jetronic (Bus EFI) is a batch-fire system, all the injectors go off at the same time. The only thing relating to those connectors that *would* matter is a broken wire, which you can check with a voltmeter or a noid light.

.. is the AFM connected to the wiring harness?

chitwnvw · Post by **chitwnvw** » Wed Mar 25, 2009 10:25 pm

Good to know Hal. We can rule that out.

We will be in Maupin around 2 Pacific time. Anyone that wants to be online and lend their expertise would be much appreciated.

chitwnvw · Post by **chitwnvw** » Wed Mar 25, 2009 10:35 pm

Can temp sensor 2 affect an engine that drastically? It was hacked with extra wire added to go to number 2. I put it back to number 3, but Mark brought up a good point, Why did they move it?

tristessa · Post by **tristessa** » Wed Mar 25, 2009 11:12 pm

chitwnvw wrote:Can temp sensor 2 affect an engine that drastically? It was hacked with extra wire added to go to number 2. I put it back to number 3, but Mark brought up a good point, Why did they move it?

Unknown why they would've moved it without more information. But yeah, TS2 can effect an engine that drastically .. possibly. There *must* be a path to ground on that circuit, either (correctly) through the sensor or (incorrect but helps troubleshoot) with teh wire securely grounded to the engine elsewhere. If the lead on the sensor itself is flakey or the connection between sensor & head isn't good (clean & securely tight), it impacts things up to the point of .. not running.

Still, I think a vacuum leak is more likely from the symptoms being described...

Oh yeah, and didja check to see if the harness is plugged into the AFM?

Post by **Amskeptic** » Thu Mar 26, 2009 5:48 am

vdubyah73 wrote:
here is a link to double relay info.
Colin has one here somewhere too.

http://www.ratwell.com/technical/DoubleRelay.html

(somewhere around here?!? Fuel Delivery!)

viewtopic.php?t=5459

As Hal tristessa mentioned, check that the harness is plugged in at the AFM, and everywhere else actually. You must inspect the little female fingers that contact the male tabs. Soulful66 and I hd a bear of a three hour diagnosis to find that the ECU plug had a little #7 (injector grounds!) issue where the holder inside the plug allowed that single wire to push back into the plug where it no longer contacted. I thik you might want to check #36 and #39 in the AFM plug. Can you please get someone else to start the engine while you move the wiper in the AFM? You would be amazed at how quickly you can narrow things down when you have your hand on the wiper to set the mixture and make sure the fuel pump stays on.
Colin

Itinerant Air-Cooled

Itinerant Air-Cooled

Troutmobile on the table