So my Z has been runnig fine except when in traffic. It heats up fast! sitting at a light or in the line at the bank, it goes up to 240 plus! WHen i rev her in park up to 5G the headers on the passengers side get a little red, not much but they do get red for the first inch comming off of the heads. Anyway, i was suspecting the cat's but they both are new, however, i do have a rattle? I incresed my fuel psi and that did not change the glow of the headers. Any ideas? lack of performance, runing hot, seems normal when driving it in town and on the freeway except for the lack of power?

 

Sounds like timing to me. Mine did this when I put my motor in my car. Try setting the timing.

 

i just adjusted my timming to factory specs of 6* btdc and my engine still rides well above 200*......still stumped

 

what about a serious vacum leak? im going to check for that also

 

NOPE, vacume is steady at 16 with larger cam than stock. I have sprayed carb cleaner over all mating surfaces and vacume lines and no change in idle. Can not understand why the passengers side heades will glow red and the drives side will not?

 

Your primary cooling fan is probably not coming on. It should kick in at about 222 deg., secondary comes in at 238. See what I am driving at. As always, probably a bad primary fan relay.

 

Danno,

I forgot to mention, I have both fans comming on via the chip. One @ 180 and the other @ 200.

 

you have more of a problem other than cooling. It sounds like one bank of cylinders is running very lean. Unless you have an obstruction in the exhaust I would look into what is going on. If you exxhaust manifold is glowing you must solve that problem first. I do not know the answer without more info, however that is where you should look. As a point of interest the ECM CANNOT control both fans. The ECM programming only controls the primary fan turn on temp. The fan switch on the passenger side of the block determines the temp of second fan operation, or AC head pressure. If one bank is that hot you have a fuel delivery problem, i.e., fuel injector pulse width. What it is I can't say but I would solve it ASAP. Danno

 

dan,

In TC, the constant's table has a section which allows you to turn on both fans. As far as the passengers side running lean, I have cleand the plugs, ran a run down the street and checked plugs and they look like they are running a bit rich. I suspect a clogged cat? I'll keep ya updated jsut good to know the outcome!

 

Craig you may have answered a question I have had for a while. Using my 89 as an example the secondary fan control has the switch, the AC pressure switch as controls for the relay according to the wiring diagram. But, there is a wire that comes from a common tie point at the two switches and goes back to the ECM. I was always under the assumption that was a sense line telling the ECM to adjust idle compensation, but from what you say it must be an output. From what you say the ECM must control BOTH fans using the coolant temp sensor, and the secondary switch in the pass side head must be a safety of some kind in case the driver in the ECM fails. What is interesting is that the TBI models operate completely independent of the ECM according to the schematics I looked at. Thanks for the heads up, I will have to look at the ECM programming sometime. Dan

 

Danno,

I think that the tbi is a little different that the tpi. If i rember right, the tbi is a 747ecm? or a 742??