Hesitation issue no 2!

Griff71 · Posted: Thu Nov 18, 2010 1:24 pm Post subject: Hesitation issue no 2!

I did carry on from Inanes previous post but my issue seems to have got worse. I have a annoying problem where my engine seems to be running on 2/3 cylinders or i am running out of fuel, no power/acceleration whatsoever then suddenly while my foot is flat to the floor it will kick in full pelt. Happens intermittently and if it wasn't for the engine running sweet in between i would have put it down to serious internal failure and started stripping the motor down or looking for another. I have said before i have done some serious miles on my conversion so i reckon some parts are possibly giving up. Did head gaskets earlier this year and heads, pistons and barrels are 100%

Previously i had a knock sensor error so i have replaced the sensor as it was cracked and fitted another. However error will not go away. Similar symptoms to what i had when i had a faulty sensor but like i said the problem is intermittent and not constant as with a faulty knock sensor. Again don't reckon there is any major issue as motor runs sweet as. However could the exhaust cause a fault with the knock sensor?

My theory: My exhaust is now coming on for 3 years old and it was a bit of a bodge when i built it but it has served me well. However it is nothing more than a seive in places and i appear to have thrown a stud out of the head/manifold flange. Now i would assume it would run like a pig anyway but would not expect symptoms like this unless the lambda sensor is being interupted by increase air, etc and telling the engine there is a problem.

Is this likely before i start fabricating a new system. Or has anyone experienced/solve a similar problem.

Thanks
Griff
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89 Crew Cab (Subaru 2.5na)
71 Drag Bug (1955cc dual 40s)
65 Ragtop Bug (low & stock)

Inane Cathode · Jedi Knight Joined: 20 Nov 2009 Posts: 225

Mine's back up and doing it again now that it has gotten all wet all over with the recent snow. I'll be watching this thread too :/

ElusiveStranger · Posted: Fri Nov 19, 2010 6:29 pm Post subject:

Running on 2, coil's dodgy or the signal to it. Total loss spark ie fires both opposing cylinders at TDC & BDC
Running on 3, dodgy lead, plug, cap or gap. Maybe mechanic failed to reconnect all 4 leads after doing work (HG's in my case *blush*)

I did get a wet lead at Putsborough one day and it caused no 2 to go AWOL on me.

Eyeball your plugs first, maybe replace.
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Griff71 · Posted: Mon Nov 22, 2010 1:52 pm Post subject:

Have checked plugs and all seem ok, have a spare Coil Pack which i could try. Not sure about Inanes situe but like i say mine is intermittent.

I will sort a new exhaust system and check my Lambda sensor is working in first instance. Just wondered if exhaust was likely to be the source of the hesitation as it seems a bit extreme that a blowing exhaust would cause an intermittent issue and would not run like a bag of s*** all the through the rev range and all of the time?

Seems like i have had no end of trouble this year.
_________________
89 Crew Cab (Subaru 2.5na)
71 Drag Bug (1955cc dual 40s)
65 Ragtop Bug (low & stock)

rjes · Posted: Sat Dec 18, 2010 4:41 pm Post subject:

If it is worse in wet weather, it'll be an ignition problem on the HT or LT side. Damp in the plug leads, coil, ignition module, or spark plugs (if the ceramic has cracked) all give the symptoms you mention, with no error codes. If it's a problem on the HT side take it somewhere very dark (away from street lighting), and you may be able to see the sparks escaping from somewhere before they get to one or more cylinders.
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Griff71 · Posted: Thu Dec 30, 2010 9:42 pm Post subject:

Have reworked exhaust and refitted/rewired lambda sensor as one wire had snagged. Plugs have all been out and checked and now seems to be running sweet.

However i have my ever occuring temp gauge flashing on and off intermittently from cold to running temp. Gauge creeps up when cruising and returns to centre at idle??!! Gauge has been fine the last few months and has now returned to annoy me.

Obvious done checked level, leaks, fan and flow. Even done a block test just in case HGs were suspect yet again. But everything is fine. So i am considering ditching the VW gauges all together. Seems the Impreza boys fit after market water and oil temp/pressure. So reckon i go this rout rather and get a genuine reading rather than messing with stock gauges any longer.
_________________
89 Crew Cab (Subaru 2.5na)
71 Drag Bug (1955cc dual 40s)
65 Ragtop Bug (low & stock)

ElusiveStranger · Posted: Fri Dec 31, 2010 2:56 am Post subject:

Can't help here fella. Haven't got a scoobie about your watercooled *spits* Wink

gauges etc. Soz
_________________
The advice you receive on here is worth the paper it's written on.
Your experiences are worth shed loads to others, including the f'ups - live and learn.
Wouldn't YOU rather learn by someone else's mistakes? So would they.

'78 Bay, 2 litre 091 box, EJ20 NA & the ashtray's on the 'right' side.
I don't lean forward for hills any more Grin

Bugger, missed out on "Live fast, die young"