Mark 1-Car bogs out then runs

[mr2tim]

Can't believe I paid $120 for 4 hours of help with the racecar.

I never ask for help with my car/hobby?

I had reached my limit on my hobby/abilities to understand what was causing the racecar to bog out when I launched it, sometimes in 2nd gear too.
(on and off for the last 4 months. )

According to the results of the troubleshooting it's the faulty ground (black and white) wire at the AFM. I grounded the negative battery terminal to the "E" groundpoint on the intake manifold and will road test it at first light.

I'm not going to give up till the car is running normally again.

Has any other MarK1 (S/C) owners ever run into this problem recently?

[Jackstand Queen]

Be sure to check to connector right at the AFM. I scrubbed my AFM connectors with sandpaper grit, then pinched them tight again. And finally stuffed lithium grease into it to prevent further corrosion.
On my AFM the connection that was most corroded was the Air intake Temperature sensor (IAT).

[HoLun]

when did this first occur? and in what condition does it occur? ie. before reaching operating temp?

did you do anything to the engine before this happened?

[mr2tim]

The car has a relatively fresh 90K OEM stock engine, it bogs out hot or cold?

I have another S/C car and have swapped the ECU,AFM,TPS,Coil,Igniter rebuilt the guts of the distributor, ran continuity checks of the wires from the AFM to the ECU, confirmed all ground points and run continuity on them all the way to the ECU "E" (grounds), new fuel pump and good pressure!

(sanded the AFM contacts Jackstand-thanks)

Problem does appear to not happen all the time just 90% of the time, just enuff to prohibit me from using the car for work purposes, which I need desparately!!.

Any fresh ideas would be appreciated from anywhere or anybody, I'm losing my perspective on what to do next.

Originally Posted by HoLun

when did this first occur? and in what condition does it occur? ie. before reaching operating temp?

did you do anything to the engine before this happened?

[muffinman]

Originally Posted by mr2tim

I'm losing my perspective on what to do next.

You could always just give it to me Tim

[Jackstand Queen]

Have you check out your ABV with a vacuum gauge?

Since you swapped all your large electronic devices. . . . . try swapping out the relays in the engine bay relay box.
There's also the circuit opening relay and the SC relay on either side of the ECU.

Have you tested your FPR? Do you have any idea what fuel pressure you are running?

All these troubles with numerous SC's lately have been making me think I should start preparing to go with a Megasquirt, or maybe an out of the box EMS.

[HoLun]

do you have an AFR gauge? even the cheap narrowband light show will help to see if its a rich bog or a lean bog, or have anything to do with fuel system at all.

[mr2tim]

Dear Ho Lun,

Sorry, racing is a hobby so I don't have a clue what the AFR is, altho, I gather from your explanation what it does and the results it gives. Is there anyother easier way to nail down if the fuel delivery system is the problem?

My fuel pressure gauge doesn't bottom out or hardly move when the "BOG" occurs, is that any indication of the total picture of the fuel delivery?


Thankss

tim

Originally Posted by HoLun

do you have an AFR gauge? even the cheap narrowband light show will help to see if its a rich bog or a lean bog, or have anything to do with fuel system at all.

[djskorch]

also, just possibly, might want to check the o2 sensor. look for my post "car bogs when cold" and it turns out that it was the 02 sensor. gl

[mr2tim]

Cool idea? I have not done a check on this but..

I will look in the book and find out where it is.

I did replace the VSV on the rear engine firewall (next to S/C) but I'm pretty sure that's not what your referring to? Maybe it's the brown thingy connnected to the S/C w 1/8" rubber tubing and bolted to the side of the S/C unit? I'll find out..

Anyway...

Yeah, Bro I did the relay swapouts at the box under the battery, no change.

When I swapped the ECU with the streetcar I did both the relays and got no change either..

Also changed out the Solenoid Resistor this weekend with no change.?? Thinking it might be injector realated?

Fuel pressure stays right up there in the 28-33 psi range and doesn't drop off when the "BOG" occurs

I can't find out where anything called the FP Relay is located? It doesn't show up in the drawings and schematics I referenced, I thought it may be located under the battery?

Have you messed with this before?

Thanks, Tim

Originally Posted by Jackstand Queen

Have you check out your ABV with a vacuum gauge?

Since you swapped all your large electronic devices. . . . . try swapping out the relays in the engine bay relay box.
There's also the circuit opening relay and the SC relay on either side of the ECU.

Have you tested your FPR? Do you have any idea what fuel pressure you are running?

All these troubles with numerous SC's lately have been making me think I should start preparing to go with a Megasquirt, or maybe an out of the box EMS.

[mr2tim]

The car got a brand new sensor in Oct of 08, wouldn't hurt to check the operation out, thanks for the suggestion..

Tim

Originally Posted by djskorch

also, just possibly, might want to check the o2 sensor. look for my post "car bogs when cold" and it turns out that it was the 02 sensor. gl

[mr2tim]

Hey Muffin,

Jeezz, I can't find time to visit even?

I've got a couple of late afternoon appt's in Coral Springs this week, maybe I could drop off the street car instead?

I'll ring you after work..

Tim

Originally Posted by muffinman

You could always just give it to me Tim

[muffinman]

Originally Posted by mr2tim

I've got a couple of late afternoon appt's in Coral Springs this week, maybe I could drop off the street car instead?


Tim

I'm not greedy i'll take either one just make sure you don't forget the title

[Jackstand Queen]

Timmie:

AFR guage, is an air fuel ratio meter. By measuring the composition of the exhaust gases, it can determine how lean or rich the motor is running. I believe they can run off an ordinary 4 wire o2 sensor.

Avoid self-hatred, don't give your Ho' Car away.
Because if you gave it to some bum wearing a tin foil hat, pushing a shopping cart full of garbage, he'd have the car working like new the very next day.

This scenario refers to Muffinman in no way, form, or fashion.

Your engine problem could be due to one or more of a hundred issues. You just have to work through the frustration and resulting depressive emotions to finally arrive at the solution. This is Skynet: . . . .. . . man vs. machine. You can't let the Machine win!

My next bit of useless advice that amounts to a wild goose chase is:

Fatigued Wiring . . . . . . . .

The 4age motor family rocks forward and backward on its motor mounts . . . . a lot.

When a twenty year old piece of wire is flexed so many degrees back and forth thousands, even tens of thousands of times, the individual wire strands begin to break off. Finally the wire is functioning of just several strands. Then it fails when overloaded.

The first area to look at is the dizzy, ignitor, coil wiring. Then I guess I'd check the wiring from ECU to the various devices. Take a new piece of wire three feet long or so of several gauges and note resistance readings for comparison.

I think if I make the leap to Megasquirt, I'd put in all new wiring to go with it.

I've worked on some domestic junk from the 60's that had been left out in the rain for decades. And believe me, the wiring on those things was toast.

[muffinman]

Originally Posted by Jackstand Queen

Avoid self-hatred, don't give your Ho' Car away.
Because if you gave it to some bum wearing a tin foil hat, pushing a shopping cart full of garbage, he'd have the car working like new the very next day.

How did you know about my tin foil hat and garbage cart , are you the one following me?



but seriously Tim if thats what you want to see in order to give me the car , i'm pretty sure i can arrange it

[Jackstand Queen]

How did you know about my tin foil hat and garbage cart , are you the one following me?

by Muffinman.

No, I'm not watching you, I just had my buddies in the CIA & FBI send me real time satellite feeds and spycam footage of you.

I must admit to a nice laugh at reading Muffinman's reply.

[mr2tim]

Thanks for writing bro,

This car is solid when it's cold and always fires up on the 1st keyup, I'm not getting any Codes on the o2 sensor probably cause it's less than 6 months old.

If you have any more ideas please pass them along.

I'm always listening,

Tim
(mr2tim)

Originally Posted by djskorch

also, just possibly, might want to check the o2 sensor. look for my post "car bogs when cold" and it turns out that it was the 02 sensor. gl

[mr2tim]

Howdy Jackstand,

Damn, I found 2 defective items on the car neither affected the problem. Can you believe it?

They were:

1. The ASC valve which apparently somehow equalizes the air chambers in the front and rear of the Supercharger soas oil doesn't get sucked or blown out of the unit. The valve didn't respond to battery current and I replaced it with a $2 part from a new Camry
(see attached replacement photos)

2. The VSV attached to the rear firewall wasn't connected to a vacuum source and thusly I believe that the blow-off valve has not been working because it probably wasn't getting a vacuum to actuate it?

I picked up a Code 24 (Air Intake Sensor) but my BGB testing reveals no problem with it's output as measured at the AFM terminal. I've tested all the wires from the ECU to the AFM (continuity checks) and all are intact in their length? I'm not sure what other tests to run on the IAT sensor/output other than those shown in the book. Why the ECU is getting this Code troubles me? I've switched the entire AFM with the one in my street car (both S/c's) and no difference was noted in the "bogging" problem, again.

With the fuel pressure being stable during these "bogging" episodes I am totally at a loss to understand the dynamics of what I'm dealing with.

The car never stalls completely and will recover operation slowly in 5-10 seconds but it's just not driveable in traffic. Runs 100% in every other aspect except this off the line start...

I'm attaching a bunch of reference items and the VSC swapout if case any of you need not to spend $100's on a new one..

Tim
(mr2tim)

Originally Posted by Jackstand Queen

Timmie:

AFR guage, is an air fuel ratio meter. By measuring the composition of the exhaust gases, it can determine how lean or rich the motor is running. I believe they can run off an ordinary 4 wire o2 sensor.

Avoid self-hatred, don't give your Ho' Car away.
Because if you gave it to some bum wearing a tin foil hat, pushing a shopping cart full of garbage, he'd have the car working like new the very next day.

This scenario refers to Muffinman in no way, form, or fashion.

Your engine problem could be due to one or more of a hundred issues. You just have to work through the frustration and resulting depressive emotions to finally arrive at the solution. This is Skynet: . . . .. . . man vs. machine. You can't let the Machine win!

My next bit of useless advice that amounts to a wild goose chase is:

Fatigued Wiring . . . . . . . .

The 4age motor family rocks forward and backward on its motor mounts . . . . a lot.

When a twenty year old piece of wire is flexed so many degrees back and forth thousands, even tens of thousands of times, the individual wire strands begin to break off. Finally the wire is functioning of just several strands. Then it fails when overloaded.

The first area to look at is the dizzy, ignitor, coil wiring. Then I guess I'd check the wiring from ECU to the various devices. Take a new piece of wire three feet long or so of several gauges and note resistance readings for comparison.

I think if I make the leap to Megasquirt, I'd put in all new wiring to go with it.

I've worked on some domestic junk from the 60's that had been left out in the rain for decades. And believe me, the wiring on those things was toast.

[M-r2d2]

hey you don't think that one of your injectors could be failing do you?

from what it sounds like to me is that at idle there isn't that much fuel to keep it running but when you say floor it and it needs all the fuel and the boost is introduced there may not be enough combustion to get all the power so the engine backs off.

hope that made seance.
jason

[mr2tim]

Thanks for writing Jason,

Once I get the car rolling there is no problem with performance up to 7,000rpm, both with boost and without.

I believe I can back-probe the injector wires for a ohm-meter readout just to be sure.

This "bog-out" comes on only when the engine is under load, when I rev the car there is no hesitation at all. Isn't that weird?

I first thought it was weak spark but swapping out the coil and igniter from my street car didn't do a thing. Then I rebuilt the distributor with guts from another one I had.

There is no drop in fuel pressure either.

Thanks,

Tim

Originally Posted by M-r2d2

hey you don't think that one of your injectors could be failing do you?

from what it sounds like to me is that at idle there isn't that much fuel to keep it running but when you say floor it and it needs all the fuel and the boost is introduced there may not be enough combustion to get all the power so the engine backs off.

hope that made seance.
jason