scalbert

But this time it is for the better...

After rebuilding the FPR last weekend everything has been doing well. The fuel pressure has remained in the correct range and rising as needed. But I have been experiencing some other minor issue which I disregarded previously but now being more attuned to the operation, I did pick this up.

With the recent chronic rain and spurts of sun I have noticed odd behavior. It seemed to run like Jekyll and Hyde. If it was very hot or unusual weather conditions it was bogging in the mid range with still a lull in power up high. I wonder if this was more noticeable due to the fuel issue being corrected, but that is now irrelevant.

In thinking back to other similar applications something dawned on me; the ESM. I had fiddled with it and not using the advice from Jens, I had not recorded the adjustments I had made. I thought I had turned it up one turn just to see. But then backed it down one half after hitting the point where the ECU reacts. And then I had thought I later turned it back the other half to the supplied setting. But maybe I didn't.

The symptoms were the same as when I turned it forward too far, a definite lull in power where it feels like the pedal requires to be pushed further than needed. This is the result of significantly reduced timing when the ECU reads positive manifold pressure. So out of curiosity I turned it back some; this made a marked difference. The big test was heading back from a customer's site this afternoon in about ninety degree heat in complete sunlight. This was through congested areas mixed with open back roads. Even when sitting for ten minutes and then getting an open stretch there was no lull in power as I had experienced. I had thought it was just the nature of this blower in the heat but I had an idea something was not right. And the dyno proved it.

As of right now the car feels great; plenty of thrust at any revs. I now somewhat suspect and am curious if my dyno was not compromised two ways. By the FPR leaning it out too much and by ECU seeing too much manifold pressure and killing power additionally. I will be back on the roller soon to test this just after I do a compression test.

But now there is a point to which I am curious about. The ESM will clamp the voltage at a certain level, which is determined to be the point just before positive manifold pressure, to prevent the ECU from pulling power and/or setting a code. I had assumed that they used a set value to be considered positive manifold pressure, which is dependant on the barometric pressure, even though an absolute measurement is used. So I wonder if the ECU does not use a set absolute value, but the set point is based on the barometric measurement (from the sensor in the ECU). Anything over this would first pull power and more would set a code.

The worst I felt the power loss was two nights ago just before a large storm came through. The baro was reading in the mid 28 inches HG (which alone would hurt power) but this felt just like timing was pulled as throttle response was terrible.

Just a thought but the car is certainly running better right now; in fact it is a pure pleasure to drive...

Smitty

Niiiiiiiiice....... ...... Glad to hear everything is A-OKAY... now go get that compression test taken care of so you you know for sure.

Smitty

scalbert

I can't find my old compression kit; doubt I had all of the right fittings anyway. So I will go pick one up next week and do the test next weekend. Kinda bites how I have to pull the blower to do the test though. But that is the price you pay...

Plus, I can install the new plugs that were supplied with the kit.

Smitty

yeah let me know what those plugs end up looking like...LOL.. prolly won't notice a thing...

So plugs come in the kit??.. Hmmmm, interesting...

typeR

this is why i thought the ESM might be benficial to us NA guys too.... Steve do you think there ;s timing being pulled on us na guys that the ESM could prevent?

Jens H.

That ESM needs to be set just so to avoid sending the ECU a signal it interprets as a potential problem .I remember we fiddled with several of them a bit to make sure we got the right reading .We used the PGM-FI tester to get the reading to where we wanted it .
Jens

scalbert

Yep, Denso Iridium plugs. It is a well thought out kit...

scalbert

In this case, still, no. In NA mod you would never see enough absolute pressure to trigger a response unless maybe you were driving at 12,000 feet.

scalbert

I was thinking that the level required may vary as barometric presure varies. This could allow for on/off issues from day to day if the level was borderline.

Jens H.

You know that is an interesting thought .If you set it up on a high pressure day then run the car it may work well yet do it on a low pressure day then run the car on a high pressure day it may screw up a bit.I remember when we did types1967 car I spoke with the powers that be at Comptech and they said that it was not that sensitive but I do not really agree with that .The voltage signal is slight so a minor adjustment on a car that has a blower could do some major things.Since boost on a blown car is dependent on weather unlike a turbo car which will archieve desired boost regardless of weather I can see where this might cause a problem .
Jens

allmotor_2000

At one point... I was thinking of using the ESM to enable boost-retard at a certain boost-level (6psi and above). Additional fuel would be easy with an AIC... but timing was tricky. I might have worked... possible 10-11psi on the stock motor... ah well!

ModAddict

In anticipation of my header install I was looking for a better way to get to that pesky allen bolt under the jack screw. I bought a 3/8 drive socket, with a 5mm allen tip, at Pep Boy's for about $4. Put that on the end of a 3, 6, and 9" extentions to make an 18" extention wich put me in the clear at the other end of the jack screw. Worked like a charm!

ModAddict

Hey Scalbert, can I borrow your boost pully for a couple of weeks? It looks like you're gonna' be awhile, and I've run out of things to do until the headers get here.

scalbert

Good idea and one I planned on testing.

scalbert

That would not be a problem. Just remember that it is the alternator pulley, not the SC drive pulley. So installation is a bit of a pain.

Just PM me your address and I will ship it out.

I am curious how other vehicles react to this and if my FPR issue was present all along. If so and the pulley can be used, you know I will eventually ask for it back.

ModAddict

I also found a set at a tool surplus store that had longer allen tips with the round ends. those would work great for the ones by the oil fill cap and the radiator hose. They only came in a set of 7 or so sizes for about $15. I may go back and get that set also.

ModAddict

PM sent. You know when the Unichip gets going, we will be looking for a bigger boost pulley.