tdr_1976 41 1 Cars Posted June 16, 2017 (edited) After doing a trouble free 107 miles with the engine conversion, last Sunday I decided to go out for a drive to get some more miles done to run the engine in. When I went to turn the engine over to start, it was really slow and not quite quick enough to spin it to start. I purchased a brand new Bosch battery, thinking the old one was starting to die. The car started without any problems, problem solved..... or so it seemed at the time. I went for a spin to a mates house, and an hour later went to start the engine, the same problem cropped up again. I was distracted when another mate turned up and was there for another half hour. I decided to try and start the car before reaching for the jump leads and low and behold it cranked up as it should and away I went. After I got home, I used a multimeter to check that the alternator was charging the battery and all was good, the fanbelt was tight enough, all earth and live terminals and points are clean and tight. I've just tried starting it again now, and it's done exactly the same thing, it does it when hot or cold.... I cannot think what could be causing this issue to be honest...... Ive tried another known good starter and was exactly the same. Is the ignition barrel known to cause this kind of problem or is there anything in the system I could check? Any help would be great. Cheers Edited June 16, 2017 by tdr_1976 Share this post Link to post Share on other sites
toolie72 67 1 Cars Posted June 16, 2017 Bad earth? See if it's the same with a jump lead from negative on battery to starter body Easiest to check Failing exciter wiring to starter? Share this post Link to post Share on other sites
tdr_1976 41 1 Cars Posted June 16, 2017 Hi mate, Thanks for the suggestions, I'll give them a try in the morning Been thinking about the exciter wire, when it was reconnected I made sure it was done with good quality connectors and heat shrink was used to seal it all up. Cheers! Share this post Link to post Share on other sites
DamirGTI 323 Posted June 16, 2017 (edited) Could be starter wiring oxidation , wiring on these can be really bad underneath the insulation cutting current flow .. try to peel off wiring insulation from the ends and see if It's blacked oxidazed copper underneath .. if so id cut and replace entire lenght of the wire with an new one If you still have OE "brown multiplug" connects , inspect and clean the connector terminals Check the main power and ground battery cables as well . D Edited June 16, 2017 by DamirGTI Share this post Link to post Share on other sites
dobboy 231 2 Cars Posted June 16, 2017 If it's a GTI6 you should check the Cold Cranking Capacity of the new battery, I've got a Bosch S4 and sometimes if feels touch and go, it always goes but sometimes it feels it's struggling to turn it over. Share this post Link to post Share on other sites
tdr_1976 41 1 Cars Posted June 17, 2017 (edited) I should have mentioned at the beginning that the car was converted to a 106 GTi J4 engine, it has catcams 708 cams fitted and a lightned 2.9kg flywheel running DTA S40pro ECU. I had a look at all cabling and bypassed the exciter on the car with a wire from the starter solenoid directly to the battery, and tried an earth directly from the battery to the starter with a jump lead, still the same. I took off my mates starter from his J4 engined 205, and it cranked the engine to start. But, after a run down the road, I got home turned it off, it was exactly the same again All the live cables from the battery are only 4 years old, and everything has been meticulously checked during the engine conversion, this issue has come up in the past few days after the original starter gave up the fight. I've run out of things to try now? Edited June 17, 2017 by tdr_1976 Share this post Link to post Share on other sites
welshpug 1,622 Posted June 17, 2017 how many volts are you getting? Share this post Link to post Share on other sites
tdr_1976 41 1 Cars Posted June 17, 2017 Hi Mei, I'm getting 14.2v when running and just over 10v when cranking normally. Share this post Link to post Share on other sites
tdr_1976 41 1 Cars Posted July 2, 2017 (edited) The cause of the problem was that the existing wiring wasn't of a high enough amperage to allow enough current flow to the starter. Sorted after using new decent cabling from the battery/cut off switch/starter. I also fitted a heat shield to the starter to prevent heat sink. Thanks to everyone for their help:) Edited July 2, 2017 by tdr_1976 Share this post Link to post Share on other sites