cumminsturbo1991 Posted May 27, 2016 Share Posted May 27, 2016 Hi I'm New to subies and trying to fix my grandmas car its a 97 Subaru legacy cutback 2.5L it was throwing the p0400 code along with a misfire on cylinder 4 I have I believe taken care of that had plugged intake ports so took the intake off replaced gasket and cleaned the ports and took the wire fro cyl4 and put it on cyl 3 vise versa and took the code off so figured bad wires and replaced them pulled,plugs and it looks good seafoam the intake and also replaced all vacuum lines now the bad side if its cold it runs great after it warmed up it acts like it wants to die it coughs and hacks my brother replaced the timing belt/chain wasn't sure what they run timing wise but he did replace it and also timing tentionor it idled beautiful but soon as its up to temp it wants to die checked vac solenoid and its working any help would be great thanks in advance Link to comment Share on other sites More sharing options...
Brighton96 Posted May 27, 2016 Share Posted May 27, 2016 It could also be 02 sensors, once they go bad and are not replaced in a timely manner the ecu will compensate by running it lean pretty much all the time. Usually you get about 120k out of them so if the mileage is close to those intervals I'd suspect them to be the problem. Link to comment Share on other sites More sharing options...
cumminsturbo1991 Posted May 27, 2016 Author Share Posted May 27, 2016 thanks for the reply I replaced bank 1 sensor 1 because it did through a code for that and that code came off and the p0400 came up upon further research I vacuum tested the egr valve and transducer and they tested fine did notice egr valve sticking open so I cleaned it and it is still doing it works freely by hand off the car but when the car is running it works hard its hard to push it up when it gets stuck up if you burp or just touch the throttle it releases back to closed more of the load hesitation is at low rpm bout 1750ish it clears up and runs great Link to comment Share on other sites More sharing options...
JHamilton117 Posted May 27, 2016 Share Posted May 27, 2016 Are you gunna replace? Let me know if it helps! Link to comment Share on other sites More sharing options...
Brighton96 Posted May 27, 2016 Share Posted May 27, 2016 I don't think the EGR will cause the symptoms you're having, its not good that it's sticking, but I don't think it's causing that issues BUT the EGR is attached to the 4th cylinder intake tube so that makes me wonder... Link to comment Share on other sites More sharing options...
cumminsturbo1991 Posted May 27, 2016 Author Share Posted May 27, 2016 that's what is baffling me iv thought about the egr being bad but I vacuum tested it and it was fine iv never had one stick open like that just today I checked again for vacuum leaks by spraying carb cleaner around the engine and no change in idle so can assume its not a vacuum leak I did get another egr from a salvage car that I know was good put it on there and same issue sticks open and runs great cold its when its up to operating temp is when it wants to die mostly when at a stop light and in drive spits till about 1750ish and clears up and runs great that's why I suspected egr but could this be maybe a fuel pump on its last legs? Link to comment Share on other sites More sharing options...
cumminsturbo1991 Posted May 28, 2016 Author Share Posted May 28, 2016 Any body Sent from my C811 4G using Tapatalk Link to comment Share on other sites More sharing options...
Brighton96 Posted May 30, 2016 Share Posted May 30, 2016 There was another thread about this I think, the other car had similar issues and I don't remember what the solution was, but cars run open loop when cold and then closed loop when hot? If I remember correctly. Link to comment Share on other sites More sharing options...
doublechaz Posted May 30, 2016 Share Posted May 30, 2016 Mostly. Also open-loop-drive when coasting (at least in MT) and when above 23% load. YMMV. Link to comment Share on other sites More sharing options...
cumminsturbo1991 Posted June 2, 2016 Author Share Posted June 2, 2016 Thanks for the info I haven't had a chance to get on but iv seafoamed it little better but in Park i revved it couple times and still has a slight miss it idles about 500rpm is that normal? It seems to miss on hard acceleration from idle to 1500 after 1700 it pulls hard and does not skip a beat iv taken it to a shop and asked them about p0400 code was told good luck they could diagnose it but it isn't cheap and hinted the diagnosis procedure is throw parts at it till its fixed or I'm broke also could a timing jump cause a p0400 code? Just wondering Sent from my C811 4G using Tapatalk Link to comment Share on other sites More sharing options...
Brighton96 Posted June 2, 2016 Share Posted June 2, 2016 Thanks for the info I haven't had a chance to get on but iv seafoamed it little better but in Park i revved it couple times and still has a slight miss it idles about 500rpm is that normal? It seems to miss on hard acceleration from idle to 1500 after 1700 it pulls hard and does not skip a beat iv taken it to a shop and asked them about p0400 code was told good luck they could diagnose it but it isn't cheap and hinted the diagnosis procedure is throw parts at it till its fixed or I'm broke also could a timing jump cause a p0400 code? Just wondering Sent from my C811 4G using Tapatalk The good news is that the vacuum line that you pour the seafoam into is connected to the 4th cylinder intake runner and it's before the EGR so that may give some interesting results. I really doubt this is anything serious, my guess is just a build up of crap from being run for so many miles. Link to comment Share on other sites More sharing options...
scoobydo2.0 Posted June 3, 2016 Share Posted June 3, 2016 cumminsturbo1991, you might want to check all the hard vacuum lines that run to and from the EGR. They have a tendency to collect moisture and rust plugged the lines which might explain how you switched to a known working EGR and it remains to be stuck open. If the vacuum source it relies on to close is plugged it won't see the vacuum. The alternative is delete the EGR if you don't have to get the car inspected, I'm sure someone will flip out that I suggest this because we have emissions systems on our cars for a reason, but I ditched mine for the same problems and haven't had issues since. I also found this from wac over on nasioc - 'I have an MY97 EJ22 with 5MT (stick). This is the only configuration I know of that does not have an EGR. But I've been running a Legacy GT ECU for the last month or so. Since all EJ25's have EGR, I've been getting an annoying "P0400 Exhaust gas recirculation flow malfunction" code. Here's how to avoid it: 1. Get a 100 ohm power resistor. It must be rated 2W or greater, or you may fry it. 2. Connect one end of the resistor to the EGR wire. It's green at the ECU connector, and terminates to an unused pin on a connector just behind the PCV port at the top passenger side of the engine block. 3. Connect the other end to the switched +12V line from the main relay. This wire is yellow with red stripes (not available at the ECU connector), and can be found at the switching MAP sensor. (Yes, even MAF cars have a MAP sensor.) No more P0400 codes! The ECU looks for a current draw on the EGR pin, but has no way of knowing if the EGR valve works or not.' Link to comment Share on other sites More sharing options...
cumminsturbo1991 Posted June 3, 2016 Author Share Posted June 3, 2016 Scooby you have any pictures of how you did yours mine does require inspection but if the light if off I can hide it so its unseen [emoji106] Sent from my C811 4G using Tapatalk Link to comment Share on other sites More sharing options...
scoobydo2.0 Posted June 3, 2016 Share Posted June 3, 2016 I would honestly check those hard vacuum lines that run under the throttle body to the EGR valve and see if they're obstructed, that's what it sounds like to me. You could bypass them and run rubber or silicone hose directly if they are blocked. The way I eliminated my EGR was by making a block off plate for the intake manifold and picked up a oil drain plug to bolt into the cylinder head, then I capped off the vac lines and performed the resistor mod.. But we don't have inspections here in Michigan, so I dump emissions controls immediately on my cars. I don't have any pics of the wiring for the resistor mod, but if you can get your hands on a wiring diagram for your car it's not too difficult since it states what pin and wire color. The only caveat is whether or not there is anything stored in your ecu about the EGR valve CEL and if they perform a sniffer on your exhaust and something turns up there. Link to comment Share on other sites More sharing options...
cumminsturbo1991 Posted June 3, 2016 Author Share Posted June 3, 2016 do they make an egr delete plate for that or is that something you have to make? this is a stupid question put where is the ecm I have an hayne manual for it just looked at the wiring diagram and it does not have the egr wire on there just a pressure switch wire which shows yellow with red tracer that switch I found on the pass side fender the egr vacuum switch does have a green wire on the switch but idk if it changes in the car lol hate wiring and emissions but im trying to fix it for grandma and iv got most hesitation out of it but ill look alittle further 2marrow morning and see what I find lol Link to comment Share on other sites More sharing options...
cumminsturbo1991 Posted June 4, 2016 Author Share Posted June 4, 2016 Did do some "tinkering" tonight and hard lines clean getting good vacuum out of all lines Sent from my C811 4G using Tapatalk Link to comment Share on other sites More sharing options...
JHamilton117 Posted June 7, 2016 Share Posted June 7, 2016 I'm dealing with a somewhat similar issue, no miss fire on the top end or in neutral, but if I'm in any gear and the rpms are 2-3k it will start stumbling. Here's to hoping I just need my spark plugs replaced... Edit: Only under load at the lower RPMs Link to comment Share on other sites More sharing options...
scoobydo2.0 Posted June 7, 2016 Share Posted June 7, 2016 cummins, I wish I still had the motor in the car to reference wires for you but I pulled it to start a hybrid 2.1 stroker build. I'll see if I can find the harness to give you some more guidance with this. Link to comment Share on other sites More sharing options...
cumminsturbo1991 Posted June 7, 2016 Author Share Posted June 7, 2016 Idk what else to do I must have missed something bit don't know what I'm getting 20+ vacuum on lines when revved iv tested egr,transducer vacuum switches ,cleaned intake ports I got what I could out of the tube that goes to cylinder4 I have a code reader that what to replace all it says is to replace motor [emoji35] Sent from my C811 4G using Tapatalk Link to comment Share on other sites More sharing options...
JHamilton117 Posted June 8, 2016 Share Posted June 8, 2016 So I found out what my hesitation under load was... Cracked porcelain on a shitty dealership spark plug install. They must have just stuffed it in there instead of babying it a bit, damn Hyundai techs. Plugs are cheap, when's the last time yours were done? Link to comment Share on other sites More sharing options...
JHamilton117 Posted June 8, 2016 Share Posted June 8, 2016 Btw my happened more when warmed up as well, I'm guessing the expansion from heat somewhere is what was letting the spark escape Link to comment Share on other sites More sharing options...
cumminsturbo1991 Posted June 8, 2016 Author Share Posted June 8, 2016 I pulled them looked great but might not hurt to pull them again maybe I cracked one if not it will give me another chance to lol would that throw a egr flow code Sent from my C811 4G using Tapatalk Link to comment Share on other sites More sharing options...
JHamilton117 Posted June 8, 2016 Share Posted June 8, 2016 Its only like $10 bucks for a good set, if you've replaced everything else, I'd do that and make sure they are gapped correctly for piece of mind, might as well if your gunna pull them anyway. No idea about an egr code. I'm still very much learning and just pointing out my own observations through life lol Link to comment Share on other sites More sharing options...
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