I am completely stumped!

[Morris]

I think I have all my vacuum leaks taken care of. The car idles much-much better, and engine vacuum is where it should be at idle. However, my vacuum readings are still bouncing and I still have a miss or something under hard acceleration.

The miss becomes more pronounced as the engine warms up.

I this a clue?

 

[aeronca65t]

Fuel map is wrong and leaning too much in response to O2 readings?

Disconnect the O2 sensor and see if it's better.

 

[eschneider]

.....I still have a miss or something under hard acceleration.

The miss becomes more pronounced as the engine warms up.

I this a clue?

Both are certainly pieces of the puzzle.

Normally, on a regular fuel injected car, the first question is: is it going into closed loop mode? From there, you start checking sensor outputs. i'm not a megasquirt expert, but there's gotta be someone here who is..... A lot of people love it, but I have heard it takes some tuning to get them dialed in, and then there is a lot of flexibility in tinkering with the maps for personal driving prefernces.

 

[Morris]

Update:

I used a work around trick from the Megasquirt manual to smooth out my vacuum signal and determined that the "miss" was caused by the erratically bouncing vacuum signal freaking out the ECU. I fixed the vacuum leaks (so I thought) and took it for a spin, and the car seemed very drivable if not totally perfect.

Gotta call from my wife's mum, seems my wife's little brother (by 12 years) who is in his 1st month of college dropped 3 hits of acid, lost his truck, wallet and phone and called his grandma early in the morning to ask her to come rescue him from the devil.So I thought, If I have to drive 45 minutes to deal with this moron, I might as well have fun...

Well somewhere between here and there my vacuum leak opened up again and the car started running scary lean. I couldn't really deal with the problem with the space cadet in tow, so I just sucked it up and drove home hoping that "closed loop mode" would keep me from melting my pistons.

I am taking a bit of break from messing with the car, because my frustration level is through the roof. I am definitely inquiring whether or not I should even keep messing with this car. I do not think this car works well with my personality. I am not very meticulous and a bit hasty and reckless. I am also impatient and easily frustrated. And even though my wife is very supportive of my project, my dysfunctional relationship with my car is bleeding into my relationship with my family. When I am upset about something with the car, I tend to carry that upset everywhere I go.

The real bummer about the situation is that I really think my fuel injection adaptation I designed is pretty clever. And I am confident that if I could ever work out all my mechanical issues, the injection would work quite well. Also, If I sell the car now, of course, I will be throwing away many $1000s of dollars invested in this project.

Ugh! Sorry for the emotional dump. I feel like a pretty big loser right now.

 

[Jim_Gruber]

Morris,

Hang in there. We've all got idiot in-laws and relatives unfortunately. Hey hang in there with the Spridget project as well. Put it away for a little while and let your noggin work on the problem and a solution will pop out.

 

[aeronca65t]

Yeah, Jim's correct on both issues.

And I know you hate to hear this but here's what I'd do:

Go *waaaay* back to Square One and put a carb on it...just a single one. And drive it for a while. A little seat-time in a Spridget is good for what ails you. Driving will refresh your sense of purpose on this project.

At the same time, work through your design issues for your FI system. Maybe re-think some of the setups and reflect upon the system.

You'll get the FI system worked out...and when you do, I want to hear about it.

But right now, make it a "driver" and go for a cruise. /bcforum/images/%%GRAEMLIN_URL%%/driving.gif

 

[kcbugeye1275]

I agree with the above. You need some enjoyable seat time with your car. Perhaps, during the time the car doesn't have this system on it, you will have that revation of an idea and it will all work out. I had an acquaintance dealing with a problem relative and he said the relative and all his friends had a collective IQ in the single digits. Get that car running on the carb and enjoy for awhile. Good luck.

 

[Glen_B]

With a bouncing vacuum signal, have you considered that the MAP sensor might be the problem? Cold solder joint, broken lead, leaky tube to sensor?
Incidently, what injector did you choose for a single injector 1500cc motor?? What fuel pressure regulator, what fuel pump? I'm just now buying these items for my 1275 A-series project and I anticipate using a single injector. It would be nice to know what you chose and why.

Thanks,
Glen Byrns

 

[Morris]

Thanks for the encouragement guys.

Glen, I am using a 45# injector from a Neon SRT-4. However, you can find 55# and 65# injectors for the SRT-4 as well. I would think you are going to want one of the larger injectors for your application. These injectors are awesome. they are very small and have a "disk type" nozzle that has a nice broad spray pattern.

The pressure regulator I am using is one of the many cheap "AEM" billet regulators available on eBay. Look around. You can probably pick one up for $20-30 as there always seems to be some kind of price war going on.

For fuel pump(s), I have a generic inline, low pressure electric pump ($35) feeding into a medium sized GM fuel filter($6.50). I also feed a return line into this filter as well as a line returning to the tank ('bout $10-$15 worth of fittings depending on where you pick them up). This acts effectively as my surge tank. You will need this. Without it, your car will die out in corners once you go below 1/2 tank. Next I have an in line EFI pump from a late 80's Ford F-150 (roughly $75 from O-Reilly's). I will try to take some pics for you soon.

If you want to keep the cool look of your SU carb, I think the injector adapter I made will perfectly for our application too. Again, I will try to get pics. It's hard because I usually don't get any free time until the kids go to bed.

Feel free to PM me if you want to chat about this stuff off line.

 

[Glen_B]

Thank you!! Good information. Most of the MS success stories are about very different setups than the one I have planned. Your arrangement is pretty similar to what I want.

I'd love to see some pics. I've finished the computer, stim and relay board assembly. They test out fine and now I'm to the point of designing the "wet" end of things. With the turbo, I think the 65lb injector will work out nicely.

Many thanks,
Glen Byrns

 

[Morris]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:]Next I have an in line EFI filter from a late 80's Ford F-150 (roughly $75 from O-Reilly's).[/QUOTE]

Oops. Meant to say EFI pump.


BTW, if you go with the 65# injector, it's going to be a real bear to get it to idle decently. Are you going with the MS-II set up. MS-II has high resolution injection code that will make it much easier for you to create a stable idle.

I have the high-res code for MSNSextra on MS-1, but I am not sure how to make it work yet.