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Adrian's '78 245 DL+16v

Is your intercooler blown? It just sounds like a massive vacuum leak somewhere man...
 
my 745 acted almost exactly like that when I burst the turbo to intercooler hose. I'd doublecheck all that hoses/intercooler/etc- maybe you popped another one off or somesuch...


M.
 
Blown hoses/popped intercooler would just make it run perfectly fine in N/A mode, megasquirtz is awesome like that.

I checked the datalog, you popped the hose at 3.3psi? And at that point it shows 100% dutycycle :-)lol:) and AFR's in the 9's. Ohh now I see the lean AFR's you were talking about, that's probably where the downpipe separated. Exhaust leak after the turbo would just be annoyingly loud, wouldn't lose much power, but I don't think I've had much more than a few largeish cracks post-turbo, and never had any big leaks pre-turbo.

It's gotta be an MS thing, poor timing, or lack of fuel (or maybe way too much). Stupid suggestion but maybe your timing belt skipped a tooth? Is the belt nice and tight? Mine broke the other day while I was driving along, thank god for non-interference! Cruising along in town and all of a sudden everything dies, luckily I had my tools and was within walking distance of a parts store that had one in stock. I was back up and running in 2 hours. It was cracked in a few places, definitely overdue, but it couldn't have been more than 3-4 years old.
 
The Aspirator said:
I checked the datalog, you popped the hose at 3.3psi? And at that point it shows 100% dutycycle () and AFR's in the 9's. Ohh now I see the lean AFR's you were talking about, that's probably where the downpipe separated. Exhaust leak after the turbo would just be annoyingly loud, wouldn't lose much power, but I don't think I've had much more than a few largeish cracks post-turbo, and never had any big leaks pre-turbo.

Yeah, maxing greentops at 3psi ftw, the assdyno says this thing is going to haul once I get it sorted. :-D

Had a pretty big pre-turbo leak (external wastegate was basically coming off), so it's possible that at low exhaust velocity, the cylinders closest to the wastegate were getting way less backpressure than those huffing into the turbo. Maybe? I'm really starting to stretch here. :e-shrug:

It's gotta be an MS thing, poor timing, or lack of fuel (or maybe way too much). Stupid suggestion but maybe your timing belt skipped a tooth? Is the belt nice and tight? Mine broke the other day while I was driving along, thank god for non-interference! Cruising along in town and all of a sudden everything dies, luckily I had my tools and was within walking distance of a parts store that had one in stock. I was back up and running in 2 hours. It was cracked in a few places, definitely overdue, but it couldn't have been more than 3-4 years old.

Ran some ideas past James a night or two ago, it's possible that I clogged up the filter and/or killed the pump, even though it's got good fuel pressure, it might not have enough flow or something.

Timing belt was one of the first things I checked, and it was normal, and also ~185psi compression across the board.

I'm going to get the exhaust back together sometime this week when new gaskets arrive, and see if that helps at all, then probably change out the fuel filter & pump if I can't adjust the tune to get it to run right. *sigh*

If all that fails I'll just put a carbed smallblock in. :rofl:

brokehoopity.

Indeed. Time to buy the benzo. :-(
 
Yeah, maxing greentops at 3psi ftw, the assdyno says this thing is going to haul once I get it sorted. :-D


I would possibly take a step back here and thinking about what else that might be telling you. The fact that it went to 100% duty possibly like that suggests other issues.

First issue: Your supply voltage should not drop 2 volts like that. Something ain't right there. You should have a nice strong 13+ volts under load, not 11.8. That ain't trustworthy IMO.


Second issue: 9:1 AFR should not be considered 9:1 AFR. If should be considered "so rich I really have no idea how rich it is". The sensor is essentially pegged.

Third issue: Your accel enrichment is psycho. Look at how the afr spikes up and down when you get on it. It "fires" 3 times at the start of the "pull", adding 4ms of pulsewidth each time. The AFR follows it - way too much.

The main problem with that scenario you don't have a stable afr BEFORE you really load the motor up, so you really cannot tell if the motor is going lean or rich or what, so you can't anticipate where the map is going to *need* to be.

4th issue: At 37kpa and ~15:1 afr your pulsewidth is 2.5. At 102kpa your pulsewidth is 12.5. Assume a 1ms opening time and get 11.5/1.5= 760% more fuel at 5000rpm at 102kpa, vs 3100rpm and 37kpa, with 15:1 afr


So your engine requires 760% more fuel under those circumstances? Doubtful.

Some math:

That's just under 300% more pressure. Now assume a 12:1 desired afr instead of 15:1.

15/12*300%= 375%

So, your actual injector open time should be more like 3.75 times higher not considering that the motor has better VE at 5000 than at 3000. Probably 30% or so.

3.75*1.3= 4.875

So 4.875 * 1.5 = 7.3ms

Plus 1ms for opening time = 8.3ms


8.3ms at 5000rpm: 69% duty cycle.

I wouldn't trust opening time, spark quality, or fuel pressure with supply voltage dropping to under 11volts under load though....

Just some thoughts.
 
I would possibly take a step back here and thinking about what else that might be telling you. The fact that it went to 100% duty possibly like that suggests other issues.

First issue: Your supply voltage should not drop 2 volts like that. Something ain't right there. You should have a nice strong 13+ volts under load, not 11.8. That ain't trustworthy IMO.


Second issue: 9:1 AFR should not be considered 9:1 AFR. If should be considered "so rich I really have no idea how rich it is". The sensor is essentially pegged.

Third issue: Your accel enrichment is psycho. Look at how the afr spikes up and down when you get on it. It "fires" 3 times at the start of the "pull", adding 4ms of pulsewidth each time. The AFR follows it - way too much.

The main problem with that scenario you don't have a stable afr BEFORE you really load the motor up, so you really cannot tell if the motor is going lean or rich or what, so you can't anticipate where the map is going to *need* to be.

4th issue: At 37kpa and ~15:1 afr your pulsewidth is 2.5. At 102kpa your pulsewidth is 12.5. Assume a 1ms opening time and get 11.5/1.5= 760% more fuel at 5000rpm at 102kpa, vs 3100rpm and 37kpa, with 15:1 afr


So your engine requires 760% more fuel under those circumstances? Doubtful.

Some math:

That's just under 300% more pressure. Now assume a 12:1 desired afr instead of 15:1.

15/12*300%= 375%

So, your actual injector open time should be more like 3.75 times higher not considering that the motor has better VE at 5000 than at 3000. Probably 30% or so.

3.75*1.3= 4.875

So 4.875 * 1.5 = 7.3ms

Plus 1ms for opening time = 8.3ms


8.3ms at 5000rpm: 69% duty cycle.

I wouldn't trust opening time, spark quality, or fuel pressure with supply voltage dropping to under 11volts under load though....

Just some thoughts.


Supply voltage issues forever plagued my GT, and when the voltage dropped, the car would fall flat on its face as though it was a MAF system car with a hose popped off. Was like spark blowout over 100kpa could be another way to describe how it felt.

However, with 13.5 volts changing nothing else, the car was absolutely beastly/perfect.

Find the voltage loss Adrian!
 
W

Supply voltage issues forever plagued my GT, and when the voltage dropped, the car would fall flat on its face as though it was a MAF system car with a hose popped off. Was like spark blowout over 100kpa could be another way to describe how it felt.

However, with 13.5 volts changing nothing else, the car was absolutely beastly/perfect.

Find the voltage loss Adrian!

Exactly. I have had/am having the same issues. It gradually gets better as I keep improving the supply.

The thing is, it's a two-edged sword. The ignition coil desperately needs as much voltage as possible as engine load increases, but injector duty cycle keeps going up with load, which pulls voltage down.

Are your coils and injectors powered from the same relay?
 
I'm lazy so I'm not going to consult the linked datalog. Any resets on the ms? could have corrupted it..

as far as fuel pressure being an issue (or flow), ramping the pressure up can put a strain elsewhere on the fuel supply system.. might have blown the hose off in the tank if you have a tank mounted walbro...?

Check the insulators on the spark plugs? if you had any kinda knock at all you could have broken that and it might be blocking spark energy hitting the cylinder..
 
Oh wow, a lot of great info here that I missed!

Basically since I last checked this thread I quit my job, started my own company, and hopefully :-)x:) will be signing a ~$3000 a month contract on Tuesday. My time has disappeared even worse than it already has, I have no money anymore, but hopefully I won't be making any more stress-related trips to the emergency room. :-D

Exhaust mani got dropped off to get surfaced today, hopefully I can get some clients in & some product out the door and find some time for das hoopt again.

Bondo: In regards to issue #4, just to get the car out the door, and get the exhaust mani heat cycled a few times, I put all the bins >=100 up to ridiculously high numbers, like 200s, just because I had no clue what was up and I wanted to stay way safe. Also,f or that datalog I'd consider anything the wideband says to be highly suspect because of the severity of the exh. leaks, but huge props for spotting that voltage drop!

I think the coil, MS, & injector power all comes from one place, which comes from the battery in the back, up to the front left distribution block, then back under the passenger's footwell to a distribution block there. Not 100% sure, but I know at least some power comes from there.

I've been meaning to rewire the whole thing, tearing out all of the vestigial wiring left over from the cold war, but I was kinda hoping to make that an "over the winter" project, and the itch is returning to get at least a few miles of love on it before winter hits too hard.


Kenny: no resets that I know of, but I'll try a reflash once I get it assembled again. Checked all the plugs when I did the comp checks, stupid rich but otherwise healthy. Those went in the trash and it got new ones with no improvement, FWIW.

No tank mounted walbro, got a 740T in-tank and the old k-jet main pump. When I did it I made extra sure to do a good job on the clamps because lord knows I never want to go back in there.
 
OK, almost two months later and I just now got back into the garage to look at the pile.

Here's what's happening:
- It's running very poorly, makes no power, won't idle, etc. Feels worse than running on 3 cylinders. I'm assuming it's running on two.
- Plugs #2 and #3 are dripping with fuel, and the #2 and #3 runners are really really hot.
- A timing light will light off on all four plug wires.

So here's what I did:
- Changed injectors.
- Changed plugs. No difference. #1 and #4 read fine, #2 and #3 read filthy rich.
- Changed the EDIS module. No difference.

Any EDIS gurus out there know what might be up?
- The fact that the coil is firing, as indicated by the timing light, makes me rule out the wiring.
- Do coils fail in such a way that they'll put out enough energy to show up on a timing light, but not enough to actually light off the mixture?
 
Although I'd hate to condemn my awesome plug wires, wouldn't hurt to measure them tip to tip with an ohm meter. Should be ~350 ohms per foot. The plug terminal might have ripped off, but usually it stays attached to the plug when that happens. Put a plug in it, ground the case, crank and look for spark?

Otherwise, yeah, edis problem.
 
It's not some crazy sequential MS tweak right? Just regular old 2 banks of injectors? Did you try swapping the injector wires around, ie put the 2 on the 1 and vice versa?

One weird thing I had was (I assume) a weird short from the leftover flux on my MS board after repairing the damage when I let the magic smoke out of it. I say assume because I found weirdness metering that went away after a vigorous alcohol rescrubbing. It's a long shot but if you've been futzing inside the box maybe give it another cleaning...


M.
 
Spent the last many months trying to build a company, finally got ~10 minutes of breathing time to look at the pile.

tumblr_kvt8zf5eY91qzolu5o1_1280.jpg


Gapped the plugs super tight & the other spark bank will fire. Ordered up a replacement coil and some other goodies to fix some issues, and hope to have it back boostuing on the road sometime February. Everybody cross fingers!
 
The hooptie's growing up! w000!

How'd the "trying to build a company" thing go?
 
The hooptie's growing up! w000!

How'd the "trying to build a company" thing go?

Good and bad at the same time, like it is. I've got more work than I can field, I can't find any good extra talent, so I'm backed up like 3-4 weeks out, and I still haven't learned to say "no", so basically FML, but hopefully it'll level off at some point and I can breathe again. :e-shrug:
 
:) Better that way than the other! I hear you though, it's been like that at work quite a few times this past year... I'm working on it, but I HATE saying no.
 
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