SugoiE7 Posted October 26, 2014 Report Share Posted October 26, 2014 Hi Gents, Long time lurker first time posting, I have been meaning to start build thread for along time and will eventually get around to writing it but for now, I have a 4AGE 16V Bigport in my AE71. I would love some input if you would be so kind as to help. My problem has recently started, in fact directly after breaking a water pump, just the front bearing of the water pump to be specific. I believe this problem was caused by the fixed fan not being balanced perfectly and couldn't handle the revs/ abuse? I may be wrong but that's not the point I'm trying to make anyway, so I have now installed two thermos to eliminate the fixed fan and a new water pump obviously. Job well done so i thought? My question to you is, why now after the said repair does my car spit and pops only under acceleration, both light and heavy footed? To complicated things more, when the car is stationary it will happily rev with no dramas what so ever. Confused? Me too! So to reiterate, car ran great, waterpump breaks, repaired, stationary runs perfect ie, idles great, revs great, very responsive, but drives like CRAP!? Now in the hope to fix my problem I've replaced the spark plugs because lets face it, it had been awhile, but as it turns out it wasn't necessary because that did not change the situation, damn! Now to be clear the timing has not been changed, the TPS has not been touched! Now before you flame me for starting yet another thread please reconsider as I have done my research and have had no luck. Could it be I haven't bleed my coolant well enough, can that really mess things up that much? What would you suggest i try? I'm stumped! Thanks in advance! Jack Quote Link to comment Share on other sites More sharing options...
rian Posted October 26, 2014 Report Share Posted October 26, 2014 (edited) Regarding the water pump, FWD 4AGE water pumps aren't designed for pulley driven radiator fans and that's probably why yours failed. You can run a pulley driven fan but you must use a RWD 4AGE water pump. And I don't think air in your coolant would cause that problem, it usually just causes an erratic idle. You should bleed it anyway because it doesn't take very long and it's not very hard. I would suggest that your run diagnostics on the engine - 4AGEs have a pretty basic on-board diagnostics system that you can find info on if you google it. EDIT: did you cook the engine when the water pump failed? Edited October 26, 2014 by rian Quote Link to comment Share on other sites More sharing options...
SugoiE7 Posted October 26, 2014 Author Report Share Posted October 26, 2014 Thanks for your reply Rian, it was a rwd waterpump originally, must of just been on its way out for it to do that then, all good it now looks a hell of a lot better with the thermos and I can be sure the pulley driven fan wont fly off and mess things up even more when thrashing! Moving on, i thought that was the case but I will be sure to re bleed the coolant just so i can check that off, i didnt think it would cause my issue, well to that extent anyway. The incident happened less than a k from home so i did continue to drive home, silly i know but only as i pulled into the driveway a small amount of steam came from the coolant overflow bottle. I wouldn't say cooked but yes it did get a hotter than normal operating temp. I will look check for any error codes when i have the chance, i was really just hoping it may be an easy one for someone out there to answer. It could be a total coincidence the problem occured after the water pump failure, ill have to go back to basics. fuel, spark, air! Quote Link to comment Share on other sites More sharing options...
altezzaclub Posted October 26, 2014 Report Share Posted October 26, 2014 steam came from the coolant overflow bottle cooked... Check for blown headgasket before chasing anything else. Do a leakdown test with a compressor because if it was leaking compression into the water system you would be losing the top tank of the rad every day. So I assume it is leaking compression between cylinders. You could first try the "start with full rad and no rad cap" and look for bubbles and overflow of water, but I don't't know if that works on a 4AGE, I haven't worked on one yet. If you get compression bubbles coming up through the radiator while the engine is cold (thermostat shut) then it is definatley head gasket goneski. If you don't get bubbles, then do the leakdown test. If it holds compression in every cylinder, change the coil/condensor whatever it is using as that would give the same symptoms of running fine on no-load but breaking down under load. Less likely I'd say as it would give a direct misfire rather that fire back up the inlet. Running lean also gives free-revving OK but spits and coughs under load. Nornally I'd look for a blocked jet in the carb, but I assume you can't have that problem... Quote Link to comment Share on other sites More sharing options...
ke70dave Posted October 26, 2014 Report Share Posted October 26, 2014 Steam coming out of the overfow bottle certainly isnt a good sign.....if you are lucky it doesn't always indiciate catastrophic failure. If there is in any suspicion of overheating, i would be making sure the headgasket is doing its job. So checking the oil to make sure there isnt any water in it and checking cylinder compression with a compression testor. And like altezzaclub suggests, check the radiator for bubbles... Do you have any water/steam coming out the exhaust? are you losing coolant at an alarming rate? Once you have made sure that the compression is ok, and the headgasket is sealing, then you can start to move on to the electrics. if the headgasket is no good, its head off time! and don't just replace the gasket, get the head pressure tested, and made flat. Pending how badly you overheated it, it might be bent beyond repair.... Do you know the history on the fuel pump? Idling and free reving fine, but breaking down under load can be an indication of lacking fuel pressure. Also take a good look around the map sensor, make sure that it is plugged in and the vacuum line is in good condition. I once had a TPS go bad on a bigport 4age, and when it was plugged in it caused the engine to run horribly. The engine will run without the TPS plugged in (just not as crisp throttle response), so an easy check of this is to just unplug the TPS and see how it goes. (i drove around for a few weeks without a TPS while looking for a new one...) Another idea is to make sure the ignition system is all plugged in properly, I belive the coil needs to be grounded to work, so if this is worked itself loose can give a weak spark (unlikely, but possible) Also i undertsand you havent changed it, but double checking the ignition timing with a timing light is also not a bad idea. Quote Link to comment Share on other sites More sharing options...
SugoiE7 Posted October 27, 2014 Author Report Share Posted October 27, 2014 (edited) Solved. Motor is not cooked. It takes a hell of a lot to cook a 4a. Started to do some investigation this arv to see what i could eliminate, to my embarrassment it turns out it was as simple as the 3rd injector wire dissconnecting its self some how, dunno. She now pulls as hard as always, maybe better! Lesson learnt, don't over think things. Edited October 27, 2014 by SugoiE7 Quote Link to comment Share on other sites More sharing options...
altezzaclub Posted October 27, 2014 Report Share Posted October 27, 2014 Haha! best outcome you could have! Quote Link to comment Share on other sites More sharing options...
SugoiE7 Posted October 27, 2014 Author Report Share Posted October 27, 2014 haha sure of it! I'm super stocked! Thanks Quote Link to comment Share on other sites More sharing options...
B.L.Z.BUB Posted October 27, 2014 Report Share Posted October 27, 2014 I spent about 12 months trying to find a fault and it was a dodgy MAP sensor plug. Could have been worse :P Quote Link to comment Share on other sites More sharing options...
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