MPFI surging since rebuild - Ruby Scoo

YouTube · Post by **El_Freddo** » Thu May 03, 2007 1:32 pm

Hey all.

The re-built engine is going well BUT, i have a surging problem on acceleration. This does not happen all the time, it can happen when the car is cold, warming or hot, lightly accelerating, hard accelerating. Sometimes its just a little bit of surging, other times its very noticable to others in the car.

What i'm thinking is that is the injectors (going to use an injector cleaner on the next tank) or the fuel regualor. The pump is a non-issue as it was used with no problems on the last engine.

The injectors and regulator have not been used by me before. I'm thinking of swapping them from the old engine to see if there's a difference (after the treatment being unsuccessful and when i can find the time).

Any ideas, suggestions or straight out "i know what this is" would be greatly appreciated.

Cheers

BlackMale · Post by **BlackMale** » Thu May 03, 2007 1:45 pm

I have no difinative answer here for you, thoughts would be...

Have you look at the fuel filter recently?
My other though would also be to recheck the timing/leads/dizzy cap/ect just to make sure theres no weird little things going on.

YouTube · Post by **El_Freddo** » Thu May 03, 2007 1:48 pm

With the engine rebuild i put in new leads and plugs. The fuel filter has 20,000km on it. And this problem is not evident all the time, sometimes its there, othertimes its not...

BlackMale · Post by **BlackMale** » Thu May 03, 2007 2:04 pm

Are all the connectors sealed/full connected? Is it possible that something is loose?

Does it make a difference on how much your fuel is in your tank? Whats the chances of you picking up gunk every now and then?

If your finding this info useless I am more then willing to stop

Its just that the intermittent issues can be a bugger to fix.

YouTube · Post by **El_Freddo** » Thu May 03, 2007 2:13 pm

AFAIK all connections are sealed and conneted properly. I drove it from Benders to Naracoorte -> Mt Gambier -> Adelaide and back to Woodend via Castlemaine. If something was loose i would have known about it. It has been doing this surging since i rebuilt it, so its not a new issue and it must lie with one of the un-touched parts.

Its only now that i've got around to posting about this. I'll try out the injector cleaner stuff and see what happens...

And i got 730km from one tank, Adelaide to Woodend

BlackMale · Post by **BlackMale** » Thu May 03, 2007 2:17 pm

Looks like I am no help then.

Dam 730km is a great number, must have had a huge tail wind

YouTube · Post by **El_Freddo** » Thu May 03, 2007 2:23 pm

BlackMale wrote:Looks like I am no help then.

Dam 730km is a great number, must have had a huge tail wind

not huge, but it was a factor

And yes, very happy. the engine also pulls well low down in the revs, just tried it out before lunch for the first time off road on some familiar tracks...

it was great - had some guys installing the recaptured water pipes look at me like "how the f*** did you get up here with that" sorta scared me cos i wasn't expecting contruction up there... fun in the mud too...

cheers for your ideas though, i'll get back to you about how it goes and what i do/don't do...

YouTube · Post by **El_Freddo** » Wed May 09, 2007 12:51 pm

I was thinking the other night that during the rebuild i replace the black injector seals with red ones. I'm thinking that these may be the problem in that they are leaking air into the manifold randomly. They weren't a tight fit but didn't think anything of it.

Which now raises the other question i thought of: Can i drop a set of turbo injectors in with out changing/upgrading the ECU? And will the current ECU tune itself up to run at the right fuel:air ratio?

Idea of this is to get more fuel to the engine quicker when giving her a good squirt. I'd like to know if this would work.

Cheers

Suby Wan Kenobi · Post by **Suby Wan Kenobi** » Thu May 10, 2007 9:18 pm

You can put the turbo injectors in there without any problem you will probably use more fuel in the process however. Your surging issue sounds like its AFM related

steptoe · Post by **steptoe** » Thu May 10, 2007 11:46 pm

730 km to a tank might lend towards it being a bit lean , i wonder if your O2 sensor is Ok. The single wire O2 sensors claim only to be good for 80,000 and if you drop them or engine has spat coolant past it or oil, its response can be slowed. I priced a Bosch for my turbo EA82T - $45 trade price and a 22mm ring spanner is handy too !!

discopotato03 · Post by **discopotato03** » Fri May 11, 2007 8:29 am

Hi guys/girls . My RX-T has this problem and I removed the injectors for cleaning which made almost no difference . When I first bought this car I suspected it had a lead/plug problem and had brand new plugs in and out because the first set were not resistor plugs like EA82-T's are supposed to run . They came out a slight very pale mustard colour which generally means lean mixtures . My car got ~ 640K/60L on the run home from Melbourne and used no oil which is pretty fair from a 250 000 K old engine . I suspect my cars problem is AFM or throttle potentiometre related and making it run lean because of it . I need to know what the output voltages of both should be and the colour codes of the signal wires from both units . One thing we did do was to remove the aluminium plug that covers the AFM's air bypass bleed adjustment screw and have a play with the idle mixture (with AFR probe in the tail pipe) . There is some scope for adjustment in the AFM itself but I'd prefer to know innitially that its working ok first .

Can anyone tell me if MPFI EA82's have known electrical issues at high mileages ?

Cheers A .

steptoe · Post by **steptoe** » Fri May 11, 2007 11:18 am

the O2 sensor for Adrian too me thinks, given it is >>edit>> I AM WRONG. READ BELOW WITH CAUTION. SH1TSPINNER AT WORK
1. an electrical item
2. wears out and gives slow readings to ecu as it ages
3. can be damaged
4. controls the lean rich factors
>>edit>> but defaults to RICH when worn or dirty

OK so maybe it is not the O2 sensor

5. easy enough and cheap enough to give it a try
6. someone else sold the car for some reason
7. me never had an EA82T running long enough to fiddle so I don't 'know'
8. i sorta like LPG in basic form coz it don't use these sensors
9. i still claim to 'know nothing' .
10. here are some hotline numbers available to the trade Bosch 1300 307040
11. Automotive service solutions like you to buy your stuff off them for their help. maybe ask if it is quiet, you are a ausubaru club member, speak nicely and they may help a little 1300 304060

12. most importantly, tell me to bugger off if you have replaced it and I missed the fact

YouTube · Post by **El_Freddo** » Fri May 11, 2007 11:48 am

The O2 sensor is less than a year old, but that said, the last engine probabily spat at least a sump worth of oil and other sh*t over time past it... could explain why the car still ran the same without it connected (i had fixed up an exhaust leak and didn't realise i had left the O2 sensor disconnected til it was running hot a few days later - and it still ran hot after it was connected)

Damn, $45 is a good price, i paid $80 for mine

Can you clean these things and they still work properly? at the back of my mind somethings saying you can clean them but they won't work after...

I'll look into this.

And last tanks of fuel went like this:
593KM - 53L -> about half of this was "city" driving, other half country/highway cruising
608KM - 51L -> probably 80% c/hw cruising
Both running 95 ron.

Cheers

steptoe · Post by **steptoe** » Fri May 11, 2007 12:31 pm

big "NOTE" in bosch book ...O2 sensors can't be cleaned !!

as O2 sensors deteriorate or contaminated it causes the average to reduce giving the impression engine is lean so ecu richens up mixture to compensate

OK SO I WAS WRONG!!! above , consider head pulled in

Xtreme_RX · Post by **Xtreme_RX** » Fri May 11, 2007 12:49 pm

The 'L' series Flap AFM Turbos do not use the O2 sensor untill there on boost & or highway driving.

YouTube · Post by **El_Freddo** » Fri May 11, 2007 12:52 pm

jono wrote:big "NOTE" in bosch book ...O2 sensors can't be cleaned !!

This would be what's in the back of my mind...

Thinking about it after a short drive, why would the engine running lean cause surging? I'm not so sure it is the O2 sensor, which then puts me onto the other suggestion of the AFM:

How do i check this? Any easy visual checks - make sure the wire is still one piece? Or will i have to check the voltage?

The other thing with both of these suggestions is the ECU is not giving definite codes. More like Jibberish, you cannot tell a long pause from a short pause even if your life depended on it (gives a 5 second light up then a series of quick to slow to semi quick flashes followed by a 5 second one again... ...). Last time i checked the memory log it had nothing to tell me.

I could be wrong here, but i think all electronics are fine, its something physical.

Wrong spark gap wouldn't do it would it? I'm running 1.1mm gap as opposed to .8mm gap, could it be this simple? the last engine didn't have this problem (and these are new plugs, not hand-me-downs)...

The injector cleaner hasn't done the trick either, i might swap the injectors on sunday and see if that changes anything.

Please, keep the ideas/thoughts flowing, all help/suggestions are appreciated.

Cheers

YouTube · Post by **El_Freddo** » Fri May 11, 2007 12:53 pm

Xtreme_RX wrote:The 'L' series Flap AFM Turbos do not use the O2 sensor untill there on boost & or highway driving.

Thanks Xtreme RX, but i have a hotwire AFM non turbo MPFI. Usefull information non-the-less.

Cheers

Point · Post by **Point** » Fri May 11, 2007 2:28 pm

increasing the plug gap without an ignition system that has enough voltage to cross the gap properly will cause it to misfire. Usually does it under load though. try closing the gap up or installing a better coil. Closing the gap is cheaper and will at least help diagnose the problem.

YouTube · Post by **El_Freddo** » Fri May 11, 2007 2:37 pm

Point wrote:increasing the plug gap without an ignition system that has enough voltage to cross the gap properly will cause it to misfire. Usually does it under load though.

This engine has no problem with load... If you've been to bendigo from melbourne and taken the calder, you would have travelled up "big hill", the name says it all.

From 100km/h at the bottom by the time you got to the top with the old engine you'd be lucky to see 80km/h in 4th and there'd be a lot of pinging going on (everything i tried to stop this detonation didn't work, the larger gap plugs stopped it a little but could have been that they were new plugs).

From 100km/h at bottom with the new engine sees you at a bit above 90km/h in 5th... a huge change.

I'll give it ago and see what happens.

One thing i have noticed is that the surging seems to stop at about 3500rpm when accelerating (could just be the speed of the engine that doesn't allow you to feel it though), when cruising there is no surging. Its always when accelerating that you can feel it. -> any ideas on this one?

Cheers

Point · Post by **Point** » Fri May 11, 2007 4:56 pm

Sounds like spark could be it, where it is just borderline. The load would be highest down low, and it gets better atomisation higher up. Definitely try the plug gap.