Lugging at speed/No power at WOT

[Gary Lewis]

Finally had time to crack open the ECU.

No obvious internal issues. All electrolytic capacitors still read good (surprising, given the age of the vehicle). No cracked solder joints or blown components (aside from a diode that the original assembler scarred when hand soldering the ground plate- it measured OK)

I then plugged it back in with the cover off and traced the signal all the way to the microcontroller chip itself. No issues... the voltage was a bit off though (0.8V at idle, 3.8 full throttle). Maybe it is legitimately out of range, but not by much.

Back together... Sometimes connections also go flakey and cause issues, so there is a small chance that with a replug it will start working again. Dunno.

Side note: unlike EFI, these feedback carbs will run without an ECU... not run well, obviously. Maybe the only benefit over EFI?

Actually, what I've read is that the feedback carbs do quite well w/o the ECU. Apparently the adjustment range is very small. Instead, I think it may be a timing problem.

Anyway, hope it works when you try it.

[ratdude747]

Actually, what I've read is that the feedback carbs do quite well w/o the ECU. Apparently the adjustment range is very small. Instead, I think it may be a timing problem.

Anyway, hope it works when you try it.

Didn't have much time to drive it yesterday after "repairs". Had to go into work for 8 hours...

From the little I could do it did seem better. May be a placebo effect though. Will test more over lunch break.

[ratdude747]

Didn't have much time to drive it yesterday after "repairs". Had to go into work for 8 hours...

From the little I could do it did seem better. May be a placebo effect though. Will test more over lunch break.

She does run better... but I am doubting the fuel economy. Also now has a code for the ECT sensor being out of range... maybe thinks it's cold and dumping too much fuel?

Sounds like I need to clean the ECU connector again... I didn't really do that last time, just unplug and replug. Unless for some bizzare reason the detected TPS issue previously was masking an ECT issue?

[Gary Lewis]

She does run better... but I am doubting the fuel economy. Also now has a code for the ECT sensor being out of range... maybe thinks it's cold and dumping too much fuel?

Sounds like I need to clean the ECU connector again... I didn't really do that last time, just unplug and replug. Unless for some bizzare reason the detected TPS issue previously was masking an ECT issue?

I'm not sure I understand where the fuel economy bit came from. But I would clean the connector.

As for the ECT, I've heard that fixing one thing on those shows up others. I don't know why as you'd think they'd all be listed, but I've heard that doesn't always happen.

[ratdude747]

I'm not sure I understand where the fuel economy bit came from. But I would clean the connector.

As for the ECT, I've heard that fixing one thing on those shows up others. I don't know why as you'd think they'd all be listed, but I've heard that doesn't always happen.

Did some checks this weekend. ECT under load (voltage measurement at sensor when plugged in) measures bang-on at cold and operating temps. Which points to either an intermittent issue I didn't happen to catch, or a faulty ECU. Will clear codes and see if the code comes back.

Performance is coming and going... better to a point. Fuel economy is 13mpg mixed driving (although I suspect it's worse since I don't think I got a full fill... or the new sending unit I installed is inconsistent?).

I haven't looked into the driveline (U joints, etc)... although if I was having drag there (bad bearings) I'd hear it. Likewise, I think I just had a ball joint start to fail (clunk when braking) so I have more suspension work in the future (not to mention the 100% dead shocks I need to replace). And that's just mechanical stuff... Point being I have plenty to do here.

[Gary Lewis]

Did some checks this weekend. ECT under load (voltage measurement at sensor when plugged in) measures bang-on at cold and operating temps. Which points to either an intermittent issue I didn't happen to catch, or a faulty ECU. Will clear codes and see if the code comes back.

Performance is coming and going... better to a point. Fuel economy is 13mpg mixed driving (although I suspect it's worse since I don't think I got a full fill... or the new sending unit I installed is inconsistent?).

I haven't looked into the driveline (U joints, etc)... although if I was having drag there (bad bearings) I'd hear it. Likewise, I think I just had a ball joint start to fail (clunk when braking) so I have more suspension work in the future (not to mention the 100% dead shocks I need to replace). And that's just mechanical stuff... Point being I have plenty to do here.

A clunk when braking can easily be the radius arm bushing, which is right under the driver or passenger depending on which one.

With performance coming and going it does sound like either bad wiring or ECU. Unless the transmission is doing something funky.

How badly do you want to maintain the original "system"?

[ratdude747]

A clunk when braking can easily be the radius arm bushing, which is right under the driver or passenger depending on which one.

With performance coming and going it does sound like either bad wiring or ECU. Unless the transmission is doing something funky.

How badly do you want to maintain the original "system"?

I'd prefer to keep it stock, mainly for financial reasons. Modification is a rabbit hole that I can't afford to go down at this time.

Electrically I'm not quite done. Still need to clean the ECU connector (since that has been suspect).

I haven't looked at anything mechanical (which does include verifying the timing mark on the balancer). I want to (and probably should), if nothing else to see what shape the engine's in so I know what I'm working with. However, the next few weeks I'm booked on work trips (leaving town in a couple hours) so I won't be able to work on it much besides weekends.

The comment on the ball joints is based on prior experience with my rangers (both TIB)... the sort of feeling I'm getting matched what was lower ball joint play in the case of said rangers. The radius arm bushings are old but last I checked were still in surprisingly good shape. The Ball joints are original lubed for life units, which to me, after 35+ years is suspect. A good shakedown test will reveal the source of play.

[Gary Lewis]

I'd prefer to keep it stock, mainly for financial reasons. Modification is a rabbit hole that I can't afford to go down at this time.

Electrically I'm not quite done. Still need to clean the ECU connector (since that has been suspect).

I haven't looked at anything mechanical (which does include verifying the timing mark on the balancer). I want to (and probably should), if nothing else to see what shape the engine's in so I know what I'm working with. However, the next few weeks I'm booked on work trips (leaving town in a couple hours) so I won't be able to work on it much besides weekends.

The comment on the ball joints is based on prior experience with my rangers (both TIB)... the sort of feeling I'm getting matched what was lower ball joint play in the case of said rangers. The radius arm bushings are old but last I checked were still in surprisingly good shape. The Ball joints are original lubed for life units, which to me, after 35+ years is suspect. A good shakedown test will reveal the source of play.

I used to travel a lot for work, so understand. Have a safe trip.

The modification thing isn't too expensive - if you can find the right parts from a salvage. Pretty sure the ECU wiring will be stand alone, like there's a coolant temp sensor that goes to the ECU but another that goes to the gauge. So you can convert w/o causing problems.

Anyway, hope you can get the stock system working properly.

As for the ball joints, you are the one feeling it, so I'm sure you are right.

[Ray Cecil]

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http://forum.garysgaragemahal.com/file/n37237/66585154_10219723129218103_610713223863205888_o.jpg

Rat Dude, I was browsing the members map and saw you are close to me. My uncle lives in Carrolton, and he drive an old Bullnose with a wooden flatbed I made a few years ago. I've been to Madison many times for the Hydroplane boat races, sat under this bridge many times. I was up there a year ago at Madison Airport getting a fun flight from Cliff Robinson in his WWII open cockpit trainer bi-plane. Good to see another member somewhat close by.

 

[ratdude747]

.........http://forum.garysgaragemahal.com/file/n37237/66585154_10219723129218103_610713223863205888_o.jpg

Rat Dude, I was browsing the members map and saw you are close to me. My uncle lives in Carrolton, and he drive an old Bullnose with a wooden flatbed I made a few years ago. I've been to Madison many times for the Hydroplane boat races, sat under this bridge many times. I was up there a year ago at Madison Airport getting a fun flight from Cliff Robinson in his WWII open cockpit trainer bi-plane. Good to see another member somewhat close by.

Ah. I've never seen the races (in thew four that have happened since I moved here in April 2016)... always is on or near my birthday, and I don't drink so being around a lot of drunks with no other purpose isn't my forte (at least that's how the fireworks are, my wife makes me go to that part ). I've been all over Indiana my entire 27 years of life... this is where I'm likely settled... I'm moving to a new position at the same employer over winter shutdown, apparently I'm "good" enough that a department I work with a lot poached drafted me out of a position I half suck at into one that I, in theory, will kick epic ass in (I'm overqualified, but the pay is the same and the vacation rules are a hair better... and less hours too!). Anyway...

 

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Updates (been a month in the making, been uber busy at work and haven't had time to truely prove things out until now):

• Discovered that my thermostat was busted and not closing. Replaced it, but cracked the housing since bozo here hasn't done a horizontal thermostat in a shallow recess like this. Lost a week waiting on a new one; my wife has Amazon Prime though her parents, but the two day shipping only works if you actually remember to click the order button

• Used a socket extension to crudely confirm TDC... right on the money. Verified that base timing is still at the factory 10 degrees BTDC.

• Discovered that my hacked choke (no stove, just the stock electric) may be an issue when warm starting on a cool day. Had "fun" starting it coming out of lunch break a couple times last week (one time having a bunch of lube techs from the Valvoline next door insist on troubleshooting things... didn't know a carburetor from a can of pop . Anybody know of an electric choke that will fit a YFA that is meant to run without a stove or any vacuum stream?

• Checked compression tonight. Got dry test pressures of (cylinders 1-6) of 135, 140, 150, 135, 145, and 140. Yes I had all plugs pulled. Maybe I'm not interpreting this right, but seems like I have a tired engine on the edge of needing a rebuild? Edit- the engine was not at operating temp. Not stone cold (drove it home from work a few hours before), but not hot off the highway either.

The thermostat helped a bit with performance, but my fuel economy is still 13MPG or so.

 

Advice? Thoughts?