Right, I really need your help guys and gals I love the 8 valve engine but I'm rather ashamed to admit that I've never owned one for long enough to really enjoy it this will change over the next few years as I now have three vehicles fitted with these lovely lumps and I intend on doing a full resto on all of them. So this is were my story starts, I am going to start with my daily. He's a bit tatty but its a very solid B3 Passat 1800 GL with only a 100 thou on the clock and it set me back 150! It has to be said I have quite a soft spot for it. The plan is to use this car to grow my knowledge of this type of engine. The problem I have is this Although the engine looks like a 8 Valve PB its actually a PF with a cat fitted. Now I'm not needlessly taking my anger out on the cat its just I have some defects with it and I have a few bits lying around my workshop that might help me get rid of the bloody thing. These include a Golf mk2 GTI downpipe and a full Jetex exhaust system and a working PB Digifant 2 ECU taken from a 1991 Golf GTI. This is the engine in question. My first question is this : My plan is to convert this PF into a PB so what other than the items mentioned above do you think I will need? All I'm trying to do is get this engine running like a good mk2 Golf gti engine, I know its in a Passat which is heavier and yes I know its never going to set the world alight but the cat that is on it at the moment is clogged almost solid and no matter what I do to it it just wont let that 8 Valve power free lol. My second qwestion is this : What is this?? Its connected to the end of the fuel rail like so. This is a close up, I would guess its some kind of pressure sensor?? Any help and advice would be much appreciated. Many thanks Alex.
Can you not just replace the cat with a straight bit of pipe and leave everything else as-is? Or just knock the guts out of the cat and refit, come to that.
That's what I would have thought. Probably a sender in the cat too. However saying that some senders in exhaust systems are known to be fitted in the line before the cat. With regards to the question 'what is this', a quick google and voila. http://www.ehow.com/facts_7700088_fuel-pressure-sensor.html
yeah you want a decat pipe, it will have a lambda sensor hole in it so straight swap job done. the sensor you're fingering is the fuel pressure switch for rad fan/fuel pump after-run system, just leave it as is. not hooked up to the ecu it runs to a relay behind the fusebox all you really need to do to up the power to gti levels is remove the cat, that should free up the lost horses. pretty sure you cant just swap the ecu for a pb one as they arnt quite the same, for one thing pb dont have a lambda but you may be able to chip it? you'll probably find the power will be good though once you have decat and tuned it up though
Thanks for the help so far guys it is very appreciated. Rubjonney, I am glad to have you here not sound like I'm blowing smoke up your **** Would you happen to know what this fuel pressure switch does why would it be linked to the fan/fuel pump? The reason for wanting to switch the ECU's was that I was hopeing to remove the lamba sensor aswell as the cat. I've checked on ETCA and the none cat PB version of my Passat was fitted with the same downpipe as the Golf Mk2 gti and it happens that I have one of those in stock. This is not me trying to scrimp as I'm fully prepaired to spend money on the car but I havent found anyone that does a decat pipe for the passat so the only other route is to make one or fit the lamba sensor to the new gti pd. Another reason for switching the ECU's is that I would really like a neat, stock looking and in the long term reliable way around the issue. Both ECU's look the same and are of the same era and as the PB ECU is not expecting to see the input from the lamba sensor I thought this might be a easy way to remove it and leave my nice gti dp unmolested. Another thought I had was that although I do not plan to turn this in to some phonebox shaped racer I would like to make the most of the power it has and with some head work at a later date I would like to get her up around the 125lb/ft so I didnt want to take the route of bashing the internals out of the cat as this will not allow the gases to run smoothly down the exhaust. And finally the PF has another strange difference, the cambelt is different. I'm not sure how as I didnt have a PB belt to hand to compare the two but I know it has a different part number and is listed as a different belt with GSF and Euro's If anyone could shed some light on this that would be cool. Really sorry this is'nt a very interesting thread at the moment but I have a few good bits in the pipeline for this old bus but I just cant get past these little issues Thanks so much for all your time and patients everyone.
i beleive its just there to stop fuel vaporising in the rail? fitted to the G60 as well but most conversions miss it out plus digifant gti dont have em either well if you do decide to delete the lambda you can still fit a cat bypass pipe, just block the hole with a bung or the old lambda. id do that ideally as the cat downpipe setup is much easier for maintenance plus putting the 8v downpipe in would be a bit of a struggle i recon. looking at ETKA, the PF cat is 191131701cx which is the same as a MK2 Golf PF one so if you can find one of those you're sorted. it looks liek they're basically same as most mk2/3 cat but the outlet is 2" rather than 2.25", so i would say a common mk2/3 pipe would fit with a reducer for your exhuast? Other issue with swapping to PF is the pinout may not be the same on the ecu, I know the PB and PB with retrofit cat differ, I'll have a look in my wiring diagrams later to check. if it was me i would skip pb and go to 2.0 8v at least, the extra low down torque would come in handy for pulling the old barge along I recon. etka shows pf and pb use the same timing belt, so not sure why gsf/euro recons its different?
thats all you need to do; - cut or knock cat out, weld straight pipe leave a mounting hole for the lambda sensor, which you will need - swapping ECU's not advisable, the PIN out's will be different and its really unnecessary because there is no advantage to it if you want more power, have the cylinder head worked upon, larger bore exhaust system, fast road cams, performance panel filter. For that kinda money you might as well do a 1.8t conversion..
I believe the pinouts on the PF and PB ECUs are the same. The only difference is the lambda feedback input is redundant in open loop PB systems. Calibration wise the PB ECU timing would be a bit more aggressive.
just double checked US PF diagram and haynes PB, both the same bar no lambda so yah problem solved if the pb downpipe straight swap and i see no reason why not, might be a bit of a git to fit with engine in i recon! if you can get it high in the air though it'll go in from underneath once split from the manifold.
Guys you are all total legends this info is so helpfull thank you so much. I will be pulling the lump soon as I'm rebuilding the cars original gearbox at the moment, I've already had the engine out once to put a temp gearbox in and it was then that the idea struck me. The original downpipe has quite a bit of corrosion so its due an overhall anyway so I will be fitting the down pipe walst the engine is out I'm hoping this will give a good gas flow and sort the horrible sound that is the thin tinny precat downpipe that is on there at the moment. I will be fitting a brand new Jetex mild steel system walst I'm there so I'm hopeing for a noticable difference, I'm not expecting to be amazed but the engine feels so strangled at the moment its horrible when you give it a nice smooth lung full the power comes in but then drops out then in then hesitates then it runs out of puff at about 5000rpm not how an 8 should behave at all! I was really hopeing to be able to just swap the ECU's so this has made my day Toyotec, What do you mean by "the PB ECU timing would be a bit more aggressive" does this mean that once the PB ECU is fitted I will have to tune the engine differently? The Haynes book of lies says they are both the same but I'm more than welcome to any advice you could give on what to set it to for the best results Again Thank you all so much for all your time and effort its really is so appreciated
