Odd one! flat spot/restrictor when accelerating hard round a left hand turn.

Carolyn · December 2, 2018, 17:24

Boy, this one is being stubborn isn't it?

If the car was in my workshop, I'd start with an thorough electronic diagnosis, then (if nothing shows up) I'd be systematically unbolting/ removing bits until I found something that wasn't as it should be...

The answer is in there somewhere.

moredun · December 2, 2018, 21:07

I suspect a failing fuel pump, seem similar symptom's on other vehicles. The rubber diaphragm inside the pump is failing causing lack of fuel pressure.

Loss of power/cutting out when accelerating. Cutting out while under high revs, will eventually fail completely.

just my thoughts ... <- :withstupid:

shnazzle · December 2, 2018, 21:26

Quote from: moredun on December 2, 2018, 21:07
I suspect a failing fuel pump, seem similar symptom's on other vehicles. The rubber diaphragm inside the pump is failing causing lack of fuel pressure.

Loss of power/cutting out when accelerating. Cutting out while under high revs, will eventually fail completely.

just my thoughts ... <- :withstupid:

Tempted to agree if leaks are not being found. It also explains the lean conditions

1979scotte · December 2, 2018, 22:20

Never heard of a fuel pump failure on our cars but it sounds logical to my uneducated ears.

moredun · December 2, 2018, 23:58

Quote from: tommytoneism on November 11, 2018, 17:12
Also the rattle wasn't there when I pulled up but started as I lifted the roof?? Only on idle and goes away when revved.

Is the alternator bolt missing anything to do with this?

Thanks again.

Lance

The alternator will be flexing on the remaining mount and possibly hitting something to give you the knocking noise when accelerating.

This needs replaced ASAP before the remaining mount breaks

<- :withstupid:

tommytoneism · December 8, 2018, 12:08

Thanks for this all,

So I took the vacuum pipes off and found a few little cracks at the end of the PCV one. I cut it clean and replaced all and tightened well. No difference.. The car starts, revs to 2K and then just dies, if I apply the pedal it dies quicker. I've ordered a new Pump/Filter kit etc, so I'll swap that out next week. I did find a similar thread about the arch bishops car : https://www.mr2roc.org/forum/index.php?topic=65086.0 that turned out to be a dodgy MAF.
So once I've done the pump, I'll take my intake off again make doubly sure there's no leaks clean the MAF and the fingers crossed. If no joy, then new MAF. Are there any other possibilities?
OK thanks again everyone for your help.

Lance.

jonbill · December 8, 2018, 12:11

Could you share what your MAF values are at different throttle positions?

shnazzle · December 8, 2018, 15:57

It really sounds like it's not getting either any fuel or any air.
It fires up, burns through the air in the manifold and dies.
You press the throttle, it adds more fuel, run out of air quicker and dies.

All very odd.

tommytoneism · December 8, 2018, 16:05

Is it possible to give you the MAF readings if I can't start it? I'll have a look tomorrow.

Yes all very odd, got to keep on keeping on!

L

jonbill · December 8, 2018, 16:37

Quote from: tommytoneism on December 8, 2018, 16:05
Is it possible to give you the MAF readings if I can't start it? I'll have a look tomorrow.

Yes all very odd, got to keep on keeping on!

L

No, rather think it needs to be running one way or another.

shnazzle · December 8, 2018, 16:41

I'd there any way you can record or broadcast Torque or the likes while (try to) run it?

tommytoneism · December 12, 2018, 17:51

OK! Had a bit of a breakthrough today, got a new can of carb cleaner. Took all the intake off again, cleaned the MAF cleaned the TB, had the battery off for approx 30 mins. All back together fired up and ran. Went out for a drive and no problem until it warmed up then still had the flat spot from 4.5k upwards but it didn't seem as aggressive. Kept driven about, quite hard and then it cleared. It didn't come back on that trip. So came home to have a look at my Torque data, but realised I'd not been recording it all!! dooh! So went out again, all fine for a couple of miles and then started flat spotting again around 4.5k upwards when I changed up say from 2nd-3rd the flat spot would be there almost straight away at 4k.. Then after only a mile of that, I revved the engine out of gear to see if it would do the same ..and it didn't, and then from there on in it had cleared and didn't do it again for 10 miles or so.

So this time I've recorded some data, but to be honest I don't know what I'm looking at, and it seems incomplete. Also this is without my Dastek back on..but I'm pretty sure that's not what was causing the issue. So if anybody would be up for having a look at the csv file and seeing if there is anything obvious? That would be cool.

Also I now have a walbro 255 and new filter. Question is it worth fitting? will it help or is it possibly overkill?

Thanks again

L

tommytoneism · December 12, 2018, 17:53

OH.. forgot to mention the knocking has gone? which I'm putting down to my makeshift heat-shield round my air filter

Carolyn · December 12, 2018, 18:24

Good to hear of the progress!

I think the big new clue is that the carb cleaner made a difference.

I've re-read the entire thread to see if you removed the throttle body and cleaned it on the bench. It would appear not.

You can't properly clean the bugger on the car. If you haven't removed it, I suggest that you do.

If you have, the only remaining item is a new decent quality Maf??

jonbill · December 12, 2018, 20:57

Perhaps another factor is that the inlet hose has been off and on again, so possible leaks at the clamps have been fixed/changed.
I'd like to take a look at the csv file. Can you put it in a Google sheet maybe?

shnazzle · December 12, 2018, 21:13

I'd love a neb at those csv files as well

tommytoneism · December 12, 2018, 21:31

A neb?

here you go : https://docs.google.com/spreadsheets/d/1o3QgLFKRQkzHgR7ub2uFiHhqxfQ3JkjJjbV8d0Ji6Fs/edit?usp=sharing

I deleted the columns that just didn't record anything, which I was confused by, because I thought there should have been more. I'll probably try another tomorrow.

Also what do you think about the fuel pump upgrade? worth doing or will I not notice any different?

Thanks again everyone, and yes Carolyn I'll have a better go at the TB now you think that may have made the difference.

Thanks L

shnazzle · December 12, 2018, 22:42

Few observations at first glance.

1) MAF values seem a bit erratic at best
2) you definitely had knock at 4194ish rpm once as it pulled 4deg timing. That's a fail-safe in action.
3) MAF flow of 110? That's rather high. Impressive if real!
4) at one point it suddenly pulls a lot of fuel. A lot. And the intake temperature is 36deg. That's awful high for these ambient temps.

All in all... A bit suspicious on the MAF

tommytoneism · December 12, 2018, 23:39

That's great thanks for that.

Yes I have a new MAF on the way.

Thanks again everyone, invaluable resource! :notworthy:

shnazzle · December 13, 2018, 00:35

Another hint at that is that your timing figures just aren't right. It's advancing too much at idle. If it was caused by fueling then it would be due to overfueling, not underfueling like we suspected earlier.

And this can in turn be traced back to your throttle body or IAC valve.

Maybe see if you can source another one from a breaker? Then you can quickly replace it and see what happens. Then you can service yours properly and swap it back when it suits

Good fun this!

tommytoneism · December 16, 2018, 18:05

Ok so I tried a new MAF, mad no difference, possibly slightly worse? So cleaned the other one again, took off all the intake again, gave the TB a good soak with carb cleaner. Cleaned the evap. Also put back dastek. So here is a link to the new torque data. It did it once maybe twice on this trip and seemed to sort itself out.. So I don't know..
Question, if the IAC valve is dirty/gummed up because it rocks/pivots could it be this that is causing it when taking a left hander? That said the last left hander of that trip..no problem.. so don't know..intermittent?

Thanks again for taking a neb! :

https://docs.google.com/spreadsheets/d/1VLEeFqelbb8-bmM7kqes7-Oi5avx6JPoXM4aSWq5RS0/edit?usp=sharing

Lance

shnazzle · December 16, 2018, 19:17

Hard to see anything wrong in those logs.
So, some more observations;

1) IAC seems to not be stuck as when cold you're idling at 1400ish which then drops to 750ish when at operating temp. Timing is also correct so it's using the IAC to achieve that, not compensating with timing. This also suggests the TB isn't stuck open. It's a pretty strong magnet so cornering really wouldn't affect it.

2) it warms up correctly
3) MAF values seem to match load
4) still some odd excessive fuel trims but no maf values to associate them with.

I'm at a loss. Fuel pump swap would be my next trial (easy to do). Then injectors.
If you've got torque, download the torque knock detector extension. Do a few runs with that with a warm engine. It monitors OBD2 knock parameters.

Also, log misfires. You'll find them in the parameters to choose.

Carolyn · December 17, 2018, 09:57

Have you undone, cleaned. and re-connected the various earths? Two on the left-hand end of the head, the crankshaft sensor (common cause of mysterious faults, down behind the crank pulley), the main earth on the gearbox?

Have you put the missing bolt into the alternator (it has to earth too!)?

If it were my car, I'd stop throwing money/parts at it for now and do the basics (Including throttle body off and properly cleaned).

tommytoneism · December 17, 2018, 17:33

Will do Carolyn, I think you're feeling my frustration. (:< >

Today though I did a trip of about 25mile, bit of traffic and bit of motorway, didn't real drive it hard, and all felt very normal and smooth. Then just as I was coming into the village to park up, gave it a blast to 6K and seemed fine until I pulled up and the idling was a bit odd like it was breathing in gulps of fueling sporadically.

Anyway I will probably change the pump/filter and have a look at the float, a it seems to stick now again.

Ok thanks again. I would have had this all done a little sooner Carolyn, only I have no parking till the weekend when I can pull it round the back of the shop next door.. My next house will have a garage, promise.

tommytoneism · December 19, 2018, 00:21

Some more data I have taken whilst at idle. :

https://docs.google.com/spreadsheets/d/1CzGCD9uUSXYf9pWr9_lr1_5P01Qhh__UqeQ7AIYgUJ0/edit?usp=sharing

I went out earlier and it was still running a bit rough and gulping when idling, then it threw an engine fault, running too lean, and when I got back, that's when I took this idling data.

So come Sunday I'm going to :

1 . take off the TB, clean properly including the Idle valve,
2. Check all hoses again,
3. Check and clean all earths,
4. Put new bolt in for alternator mounting,
5. Change fuel pump and filter.

Can you think of anything else I should check/clean?

OK thanks again, everyone. It's good to not feel alone with this!