Strange engine behaviour

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  • The Spanish
    S2Forum Maniac
    • Nov 2003
    • 719

    #1

    Strange engine behaviour

    Ok. I have had this problem for a long time. But I think is just not one thing.

    Engine behaves a little bit strange, the problem is that not always.

    Things that happen:
    1. I han hear a buzz noise from the right side of the car in the back. Only when I am accelerating from stand still very gently. After trying to figure it out for some time I have noticed it is only when fuel tank is low, so I think it is the fuel pump.

    2. Sometimes I have idle problems. Specially when I enter the city after a motorway run. It will happen for around 5 minutes. When I stop revs drop to around 300 rpm, sometimes it even stalls.

    3. Power delivery is not very good. When I accelerate hard, around 3500 rpm I feel as I don't have all the power there. The sensation is as the overboost protection was going to engage. I dit fit the Samcos and IC O-ring mode and since then I have not had any overboost protection kicking in, but I still feel the power is not there. The stange thing is that somedays the power IS THERE and the car really flyes.

    Please some suggestions.

    I am going to start the engine rebuild now as I have all the bits so this is going in (RS2 IC already in) If I need to change something else this is the time.

    - RS2 IM, Turbo, EM, Cams, Injectors, Fuel preassure regulator
    - Marco's Downpipe and a new Lambda I ordered (std)
    - Oil pump, Water pump, Timing belt (Std)
    - Fuel pump (Std)

    Could the MAF be my problem? I am not changing it

    I thought all my engine problems where cause by and air leak, but now the Samcos are in, the engine is running better, but not perfect.

    Regards and sorry for the long post ,

    Rafael
    94' RS2 Coupe TT (Twin Torsen )
  • The Spanish
    S2Forum Maniac
    • Nov 2003
    • 719

    #2
    Originally posted by The Spanish
    Ok. I have had this problem for a long time. But I think is just not one thing.

    Engine behaves a little bit strange, the problem is that not always.

    Things that happen:
    1. I han hear a buzz noise from the right side of the car in the back. Only when I am accelerating from stand still very gently. After trying to figure it out for some time I have noticed it is only when fuel tank is low, so I think it is the fuel pump.

    2. Sometimes I have idle problems. Specially when I enter the city after a motorway run. It will happen for around 5 minutes. When I stop revs drop to around 300 rpm, sometimes it even stalls.

    3. Power delivery is not very good. When I accelerate hard, around 3500 rpm I feel as I don't have all the power there. The sensation is as the overboost protection was going to engage. I dit fit the Samcos and IC O-ring mode and since then I have not had any overboost protection kicking in, but I still feel the power is not there. The stange thing is that somedays the power IS THERE and the car really flyes.

    Please some suggestions.

    I am going to start the engine rebuild now as I have all the bits so this is going in (RS2 IC already in) If I need to change something else this is the time.

    - RS2 IM, Turbo, EM, Cams, Injectors, Fuel preassure regulator
    - Marco's Downpipe and a new Lambda I ordered (std)
    - Oil pump, Water pump, Timing belt (Std)
    - Fuel pump (Std)

    Could the MAF be my problem? I am not changing it

    I thought all my engine problems where cause by and air leak, but now the Samcos are in, the engine is running better, but not perfect.

    Regards and sorry for the long post ,

    Rafael
    Oh! I forgot.

    I think the fuel consumption has gone up also.
    Without trashing it and in a combined drive. 70% open road, 30% city I get around 18 litres per 100 Km that works out around 15 mpg without excesive abuse (No "Driving miss Daisy" style either )

    Cheers,
    Rafael
    94' RS2 Coupe TT (Twin Torsen )

    Comment

    • The Spanish
      S2Forum Maniac
      • Nov 2003
      • 719

      #3
      No suggestions?
      94' RS2 Coupe TT (Twin Torsen )

      Comment

      • newsh
        S2Forum Obsessed
        • Aug 2003
        • 16226
        • Country: United Kingdom

        #4
        I have that noise from the back when the tank is nearly empty, I figured it was vacuum in the tank, not sure if its supposed to be like that or not actually. When I open the filler cap the air rushes in "squoosh"..
        You may find things are better when you fit the new fuel pump, do the filter too while you're at it. Both of my cars have been absolutely transformed with new pumps and filters. I'd recommend the Motorsport pump if you're going up to RS2 spec.
        Another thing worth checking is the MAF connector, carefully clean the contacts and apply a little silicon grease. Make sure the contacts are actually contacting (if you see what I mean) Someone here posted about squeezing the female contacts closed a little with a tiny screwdriver, be careful though as you could easily damage the contact.
        HTH

        S2 Coupe 3B Project


        Ur quattro restoration

        S2 Avant

        Boost is the new rock and roll!
        sigpic

        Comment

        • The Spanish
          S2Forum Maniac
          • Nov 2003
          • 719

          #5
          Originally posted by newsh
          I have that noise from the back when the tank is nearly empty, I figured it was vacuum in the tank, not sure if its supposed to be like that or not actually. When I open the filler cap the air rushes in "squoosh"..
          You may find things are better when you fit the new fuel pump, do the filter too while you're at it. Both of my cars have been absolutely transformed with new pumps and filters. I'd recommend the Motorsport pump if you're going up to RS2 spec.
          Another thing worth checking is the MAF connector, carefully clean the contacts and apply a little silicon grease. Make sure the contacts are actually contacting (if you see what I mean) Someone here posted about squeezing the female contacts closed a little with a tiny screwdriver, be careful though as you could easily damage the contact.
          HTH
          I also get a huge "suoosh" of air when I open the fuel cap. But this has happen since ever. Thought it was normal.

          Will try to clean the MAF connectors.
          94' RS2 Coupe TT (Twin Torsen )

          Comment

          • newsh
            S2Forum Obsessed
            • Aug 2003
            • 16226
            • Country: United Kingdom

            #6
            After that maybe you could fit the new fuel pump and filter before tearing the engine down to fit the RS2 parts?

            S2 Coupe 3B Project


            Ur quattro restoration

            S2 Avant

            Boost is the new rock and roll!
            sigpic

            Comment

            • newsh
              S2Forum Obsessed
              • Aug 2003
              • 16226
              • Country: United Kingdom

              #7
              Do you need to change the rod bearings and head gasket? Or is it an ABY?

              S2 Coupe 3B Project


              Ur quattro restoration

              S2 Avant

              Boost is the new rock and roll!
              sigpic

              Comment

              • The Spanish
                S2Forum Maniac
                • Nov 2003
                • 719

                #8
                Originally posted by newsh
                Do you need to change the rod bearings and head gasket? Or is it an ABY?
                It is an ABY.

                But I am changing the Head Gasket also just for safety.
                94' RS2 Coupe TT (Twin Torsen )

                Comment

                • Bibby
                  S2Forum Extremist
                  • Aug 2004
                  • 1043
                  • Country: England

                  #9
                  Off Topic, but I'll keep an eye out for your motor at Christmas Rafael.

                  My mother is from Madrid, we'll be over for a few days visiting family.
                  acidtrax

                  Comment

                  • The Spanish
                    S2Forum Maniac
                    • Nov 2003
                    • 719

                    #10
                    Originally posted by Bibby
                    Off Topic, but I'll keep an eye out for your motor at Christmas Rafael.

                    My mother is from Madrid, we'll be over for a few days visiting family.
                    When are you coming?

                    Following the topic:

                    I have cleaned the MAF connector. I have found a strange thing. Where the cable connects the MAF there are 6 male connectors. The cable that clips into the MAF has 6 spaces to fit the 6 male connectors. But only 5 of the 6 Females holes on the cable have a metal female connector. The one towards the left has only the hole but without any metal female connector.

                    I hope I have explain everything correctly.

                    Is this normal all the cable that goes into the MAF has 6 holes with 6 metal female connectors to fit the 6 male connectors from the MAF?

                    Thanks anybody for checking this,

                    Rafael
                    94' RS2 Coupe TT (Twin Torsen )

                    Comment

                    • S2sedan
                      S2Forum Enthusiast
                      • Aug 2004
                      • 189

                      #11
                      Rafael,

                      I got a faulty MAF too, it sometimes works perfectly, and sometimes don´t... the consumption gets instantly high when not working as it should. Try clean the hot wire and change your probe. If you don´t have any leak ... it should be OK. Have checked your coils and spark plugs too ???
                      S2 Limo sold !!!
                      M5 E34 with some mods in the garage
                      sorry, but much happeir now !

                      Comment

                      • The Spanish
                        S2Forum Maniac
                        • Nov 2003
                        • 719

                        #12
                        Originally posted by S2sedan
                        Rafael,

                        I got a faulty MAF too, it sometimes works perfectly, and sometimes don´t... the consumption gets instantly high when not working as it should. Try clean the hot wire and change your probe. If you don´t have any leak ... it should be OK. Have checked your coils and spark plugs too ???
                        Thanks a lot.

                        Can you check that your MAF connection cable has 5 female metal connectors and one hole without a female metal connector.

                        Because I don't know if I am missing the one to the left of the cable.

                        Rafael
                        94' RS2 Coupe TT (Twin Torsen )

                        Comment

                        • S2sedan
                          S2Forum Enthusiast
                          • Aug 2004
                          • 189

                          #13
                          I can do it at lunch time give me 2 hours more and I ll post the answer.

                          cheers eduardo
                          S2 Limo sold !!!
                          M5 E34 with some mods in the garage
                          sorry, but much happeir now !

                          Comment

                          • The Spanish
                            S2Forum Maniac
                            • Nov 2003
                            • 719

                            #14
                            Originally posted by S2sedan
                            I can do it at lunch time give me 2 hours more and I ll post the answer.

                            cheers eduardo
                            Just to be clear
                            See picture

                            Thanks a lot
                            Attached Files
                            94' RS2 Coupe TT (Twin Torsen )

                            Comment

                            • Mihnea
                              S2Forum Extremist
                              • Jul 2003
                              • 1288
                              • Home: Belgium Current: United Kingdom

                              #15
                              Rafael, this is ok, the MAF only has 5 connected pins inside of it, not more.

                              BTW, how much boost are you running? can you measure boost in 3rd gear WOT from 1000 RPM and give me boost at 4k, 6k and 7k, and the RPM you're getting full boost at? Maybe do it in 4th too if it's safe to do it in Madrid...

                              Cheers,

                              Mihnea
                              '98 Silver Grey 2.7T S4, dual 2.75" turbo back exhaust with no cats, FMIC, BIG injectors, 10 Bar motorsport fuel pump, modded RS4 turbos, tubular exhaust manifolds, custom intakes, RS4 MAF, Bilstein PSS9, H&R ARBs, 19" BBS CH, custom remap, 511 BHP/505ft-lbs

                              www.MRCTuning.com
                              info@MRCTuning.com
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