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Engine revs high when reversing and turning Syncro AAZ

PostPosted: 15 Jul 2018, 22:04
by Iridium
1.9 t aaz syncro - all tyres the same tread depth

Hello All,

when I reverse and turn into our driveway after approx 10+ mile journey, the engine uncontrollably revs high. Although, from a cold start and reversing/ turning after only a few metres, this doesnt happen.

My thoughts are that the VC is tight but I welcome your views.

Has any of you had or got this prob

will this cause drivetrain or other damage if I continue turning and reversing

Regards

Re: Engine revs high when reversing and turning Syncro AAZ

PostPosted: 16 Jul 2018, 06:59
by silverbullet
Do you mean that the engine revs stay high when you lift off the gas pedal? In which case, its a throttle cable fault.

If it revs high with very little forward motion, the clutch is slipping.

If its a very tight/steep turn onto ypur drive (van on 3 wheels) and it revs high, then the VC has failed "open" when hot, so you are spinning a wheel in the air.

Cant think of any other conditions that would cause over-revving.

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Re: Engine revs high when reversing and turning Syncro AAZ

PostPosted: 16 Jul 2018, 07:16
by Aidan
do you have power steering ?

Re: Engine revs high when reversing and turning Syncro AAZ

PostPosted: 16 Jul 2018, 16:55
by Iridium
Hello



In grateful reply the van doesnt have power steering.

The revs increase uncontrollably even with my foot off the accelerator and the clutch depressed when turning and reversing, revs then gradually decrease.

When reversing into the drive, all four wheels are on the flat and I drive at approx 5mph

All forward motion is fine and the van drives without clutch slip or any unwanted high revving akin to a sticking throttle cable

Regards

Re: Engine revs high when reversing and turning Syncro AAZ

PostPosted: 16 Jul 2018, 17:17
by Aidan
maybe the accelerator cable or the lever on the pump is catching on the engine lid when reversing because the engine moves when under load in reverse, the AAZ isn't original fitment to the vehicle so the installation will be some sort of compromise depending on which pump, lda, pump lever, cable, cable stop etc.. is fitted
the 1.9 engine is taller than the 1.6 originally fitted, to fit one under the lid properly requires modification to the engine lid, usually involving cutting and cover plate I believe, it may depend on which engine lid you have (steel or fibreglass), and what is on top of it, ie a pile of heavy objects causing the lid to be deformed closer to the pump
if this is a recent issue has anything changed and if you try it without the engine lid in place does it happen ?

Re: Engine revs high when reversing and turning Syncro AAZ

PostPosted: 16 Jul 2018, 18:24
by silverbullet
Good point. Torque reversal and a diy throttle arm on the pump that fouls the engine cover would do it. Just enough drag on the insulation to let it slowly shut off.
A photo or two would help, mr iridium.

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Re: Engine revs high when reversing and turning Syncro AAZ

PostPosted: 17 Jul 2018, 17:20
by Iridium
Many thanks for your replies Aidan and silverbullet.

I do indeed have some heavy objects on the plastic engine lid which are moved regularly

I will act on your advice and information during my day off tomorrow and report back.

Re: Engine revs high when reversing and turning Syncro AAZ

PostPosted: 18 Jul 2018, 08:10
by jebiga41
The throttle or even the pump (maybe the lda slightly on some) shouldn't interface with the engine lid on a Syncro as the engine sits lower on a Syncro thus eliminating the need to cut a hole (only on 2wd) sounds like you your throttle cable is either rusty or full of dirt can happen more regularly on a hrs as the Los drive have a rubber cover to keep out the dirt go under Neath and clean off all dirt underneath the pedal area and power wash there and your engine bay (protect the alternator with a plastic bag) then lubricate both ends of the throttle cable with wd40 or penetrant oil of your choosing it possible getting someone to work the peddle by hand as you spray (use the straw to get it in the there grease the linkage around the bottom of the pedal and should sort it check for breaks in the accelerator cable cover and replace if needed with new should sort it

Re: Engine revs high when reversing and turning Syncro AAZ

PostPosted: 18 Jul 2018, 18:25
by Iridium
Hello All

Thanks for your help with this one, and you've helped me solve the problem.

I took all my junk out of the back of the van and investigated. The accelerator mechanism was fouling the fiberglass engine lid and causing the accelerator to stick when reversing. I reversed with the lid off (engine hot and cold for what it was worth) and prob solved. The fiberglass lid does flex with weight on top and Im now conscious about how I use the van when rear loading for work.

Apologies for the obvious arrow and circling on the photos

Picture 1 shows the accelerators mechanism's point of contact

Picture 2 shows deposited white fibreglass dust from contact with the lid

Picture 3 shows the area where the foam had originally been cut away

Picture 4 circled in red is the area of contact between engine and lid.

Cheers All

Sean


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Re: Engine revs high when reversing and turning Syncro AAZ

PostPosted: 18 Jul 2018, 19:41
by jes*b
Classic thread. Well done to all

Re: Engine revs high when reversing and turning Syncro AAZ

PostPosted: 18 Jul 2018, 19:59
by syncroandy
:rofl

Re: Engine revs high when reversing and turning Syncro AAZ

PostPosted: 18 Jul 2018, 22:06
by silverbullet
That throttle arm has some lovely welding on it...

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Re: Engine revs high when reversing and turning Syncro AAZ

PostPosted: 19 Jul 2018, 22:22
by jebiga41
:run might want to invest in a set of these?